Subject: Re: FILTERS From: RADIOTEL@....... Date: Sun, 1 Oct 2000 15:02:25 EDT PSN MEMBERS I have a long period (20 sec.) Lehman sensor and live in So. Calif. where there is usually a lot of seismic activity between 1.1 and 2.5 magnitude. Could someone advise me of the appropriate frequency filter I should have to monitor quakes at long distance (worldwide) and concurrently the ones that happen locally. Should it be a low pass filter set at 3hz, 10hz or 20hz? Or do I need a separate short period seis. for local quakes? Jim Allen Cerritos, Calif. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FILTERS From: Karl Cunningham karlc@....... Date: Sun, 01 Oct 2000 19:52:25 -0700 Hi Jim -- Also living in So. Ca, I looked at a few of my event record for events in the 50-100km distance range. There is significant energy out to about 6Hz, and to 10Hz for some events. I believe that the closer the event, relatively more energy will be seen at higher frequencies. Given that, I'd use not less than a 10Hz filter. 20Hz or more may be better. Then, see if you can still get distant events without them being swamped out by noise. If they are, it may be necessary to have more than one channel, each with a different filter. They can all originate from the same output of your Lehman. If you use Winquake, you can use the filtering capability to see what it looks like before you build hardware. When building hardware, I'd suggest a multi-pole filter (Bessel characteristic), if that's feasible. Regards, Karl Cunnihgham La Mesa, Ca. At 15:02 10/1/2000 EDT, you wrote: >PSN MEMBERS >I have a long period (20 sec.) Lehman sensor and live in So. Calif. where >there is usually a lot of seismic activity between 1.1 and 2.5 magnitude. >Could someone advise me of the appropriate frequency filter I should have to >monitor quakes at long distance (worldwide) and concurrently the ones that >happen locally. Should it be a low pass filter set at 3hz, 10hz or 20hz? Or >do I need a separate short period seis. for local quakes? >Jim Allen >Cerritos, Calif. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FILTERS From: ChrisAtUpw@....... Date: Mon, 2 Oct 2000 18:33:05 EDT In a message dated 01/10/00 20:02:56 GMT Daylight Time, RADIOTEL@....... writes: > Should it be a low pass filter set at 3 Hz, 10 Hz or 20 Hz? Or > do I need a separate short period seis. for local quakes? Dear Jim Allen, Following Karl's letter, out of curiosity I put 10, 15 and 20 Hz Bessel Calculations in the Burr-Brown Filter programme Filter2.exe @ http://www.burr-brown.com/download/ABs/AB-034.pdf or call www.burr-brown.com/applications/ then go to Application Bulletin #34 Press [F2] to plot and use the keyboard arrows to move the yellow X cursor. Apart from the seismograph signals, you may need to consider a) environmental noise of wind, traffic, etc. which can start around 20 Hz and also b) 60 Hz electricity, both magnetic field and vibrations. With a 6 pole Bessel Filter, 60 Hz is only 30.8 dB down for a 20 Hz filter, 45 dB down for a 15 Hz and 65 dB down for a 10 Hz. A 10 Hz filter is 6 dB down at 14 Hz, 14 dB at 20 Hz and then drops away fast. The Bessel characteristic is much more 'round shouldered' than the others, but it preserves the wave shape. You also need high A/D sample rates to record high input frequencies. If you are recording everything, this effects the storage space required. Please forgive me if I have been 'stating the obvious'. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: low-pass filters From: sean@........... Date: Mon, 2 Oct 2000 22:05:14 -0500 (CDT) Jim, Carl, Chris, and co. Regarding seismic low-pass filters vs urban noise: (I have touched on this previously:) For years we have found that an acceptable compromise for the low-pass filter for a seismic station in an urban setting is about 3 hz. We actually use 2.7 hz because it is the mechanical period of the Wood-Andersion torsional optical seismometer that has been used even recently in major stations because it is the actual basis for the Richter scale, with a static magnification of 2500 at 1 hz. By urban setting, I mean the St. Louis Univ. campus vault under the old gym on a pier that Macelwane built in 1923. It is within a km or so of freeways, railroads, and a foundry. And of course the gym and new recreation center aren't exactly quiet settings. Nonetheless, we are able to record M 3.0+ events at New Madrid, 200 km away. As Chris pointed out, 60 hz AC noise is well attenuated by a 3 hz filter. As for quake data, nearfield events (< 50 km), will arrive with higher frequencies, but still have a spectrum rich in frequencies below 3 hz, so are well recorded. With the smooth roll-off of the phase-linear Bessel response, 10 hz is not that far down. For some time I have posted the schematic of the seismic preamp and 4-pole filter that has been used in over 100 telemetry stations from Alaska to Greece. The filter design is from the NASA filter handbook (details were posted). The schematic shows options for frequency scaling, as for a 2.7 second "Wood Anderson Seismometer" response that works well in an urban setting with a 15-second long period seis like a Lehman horizontal as input. at: http://www.eas.slu.edu/People/STMorrissey/index.html stmmisc.html" PSN INFO ... SLU Seismic Network For the "station" here in my basement, about 10 meters from a street, I use a corner at about 2 hz for the broadband vertical just to keep the car/truck noise to less than 2 mm on the drum record. I am interested in teleseismic events (1 second to hundreds of seconds) anyhow. Even so, the latest M3.9 in NE Arkansas recorded clear P and S phases, with Lg about 10 mm. Unless you are running a tight (10 km spacing) network of stations to record micro- earthquakes (M<2), you don't need high frequencies. You also run into seismometer resonances (the famous L4-C gets very ringy at 16 and 22 hz), so even networks have peak responses at 10 to 20 hz, which still requires sample rates of 20 to 40 per second. The "standard" instrument for the new global network is the STS-1, which has a peak frequency response of 10 hz, so the VBB sample rate is 20 per second. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismograph From: Doug Crice dcrice@............ Date: Sat, 07 Oct 2000 15:13:52 -0700 Take a look at this one folks, it is a set of three actual earthquake seismometers on ebay. One vertical, two horizontals and some electronics. Sean could probably tell you what they are, but they look like short-period sensors. United Electrodynamics was one of the predecessor companies to Teledyne UED later merged into Geotech. Here's the link: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&tc=ps&item=458889972 -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Stable Levitation, web site, with pic's From: The Lahrs johnjan@........ Date: Sun, 08 Oct 2000 14:37:00 -0600 I think the new URL is: http://www.earthtech.org/magnets/lev.html John At 09:29 PM 9/23/99 , you wrote: >Hi All, > >Not exactly seismic orientated, but perhaps of >interest to afew on the list. > >Robert Lamb forwarded this interesting web site >reference. > >http://www.eden.com/~little/index.html * John C. and Jan H. Lahr *JohnJan@........ * 1925 Foothills Road * Golden, Colorado 80401-1718 * (303) 215-9913 * http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS Clock Receiver From: Jeff Batten jeff.batten@........ Date: Tue, 10 Oct 2000 14:16:12 -0700 Hello, Does anyone know where I can get a simple gps receiver that outputs a TTL pulse on the second. Thanks Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GPS Clock Receiver From: Larry Cochrane cochrane@.............. Date: Tue, 10 Oct 2000 15:25:03 -0700 Jeff, Check out my GPS timing system at http://www.seismicnet.com/gps/index.html. Larry Cochrane Redwood City, PSN At 02:16 PM 10/10/00 -0700, Jeff Batten wrote: > >Hello, > >Does anyone know where I can get a simple gps receiver that outputs a TTL >pulse on the second. > >Thanks > >Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GPS Clock Receiver From: Philip Schmidt pgschmidt@............... Date: Wed, 11 Oct 2000 20:22:15 +0930 Dear Jeff I use a GPS receiver from GARMIN. It is called a GPS 35-HVS you can find information about it on there web site http://www.garmin.com/products/gps35/ The unit ouputs GPS NMEA standard information which the specifications will tell you about, It also outputs RTCM data for differential location work. However most importantly and in your case it has a PPS (pulse per second) output which has to be enabled to work and beyond that only after it has locked onto the satelites. It is fully encased so it can be left outside the unit has a built in antenna and a flying lead of about 4m. It is roughly the size of a computer mouse. Any further help don't hesitate to ask Philip Schmidt Adelaide South Australia At 02:16 PM 10/10/2000 -0700, you wrote: >Hello, > >Does anyone know where I can get a simple gps receiver that outputs a TTL >pulse on the second. > >Thanks > >Jeff >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GPS Clock Receiver From: Bob Smith bobsmith5@........ Date: Wed, 11 Oct 2000 11:01:47 -0400 The preferred choice for precision timing applications is the Motorola UT PLUS oncore GPS receiver. You can purchase ready to run examples of these at http://www.synergy-gps.com If you want to follow current trends in GPS based precision timing join Dr. Tom Clarks TACGPS email list at the http://www.tapr.org web site. Happy timing, Bob Smith Jeff Batten wrote: > > Hello, > > Does anyone know where I can get a simple gps receiver that outputs a TTL > pulse on the second. > > Thanks > > Jeff > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: it happened again From: "dilek bagceci" dilek_bagceci@........... Date: Thu, 12 Oct 2000 08:12:38 GMT When will it be earthquake in Istanbul ? Do you know? I wait to reply from you .Bye _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismic sensors From: Doug Crice dcrice@............ Date: Thu, 12 Oct 2000 14:10:36 -0700 Does anybody recognize these "seismic sensors"? Since they come from the area of Mt. Hood, might they be micro-earthquake gear for tracking volcanos? http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=460949352 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic sensors From: Steve Hammond Shammon1@............. Date: Thu, 12 Oct 2000 16:05:10 -0700 Doug, I have seen gear like this at the USGS in Menlo Park. Maybe John Lahr can comment. It was about 4 years ago and Chris Detel, a USGS tech, who had moved from the seismic group to the volcano group, was working on a remote sensing system for use around active volcanoes. These sure looks like some of the same type of stuff I saw sitting on a test bench. $750 seems like a low bid for this type of gear. The stuff Chris had also functioned as an array. Regards, Steve Hammond PSN San Jose Doug Crice wrote: > > Does anybody recognize these "seismic sensors"? Since they come from > the area of Mt. Hood, might they be micro-earthquake gear for tracking > volcanos? > > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=460949352 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic sensors From: The Lahrs johnjan@........ Date: Thu, 12 Oct 2000 18:11:32 -0600 At 05:05 PM 10/12/00 , you wrote: >Doug, I have seen gear like this at the USGS in Menlo Park. Maybe John >Lahr can comment. Hi Steve, I don't recognize them, but maybe Ed Cranswick will! John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic sensors From: "Al Allworth" allworth@.............. Date: Thu, 12 Oct 2000 17:27:32 -0700 I suspect these are military footstep detectors. _______________________________ Al Allworth On the Beautiful Southern Oregon Coast ________________________________ ----- Original Message ----- From: "Doug Crice" To: "PSN-L Mailing List" Sent: Thursday, October 12, 2000 2:10 PM Subject: Seismic sensors > Does anybody recognize these "seismic sensors"? Since they come from > the area of Mt. Hood, might they be micro-earthquake gear for tracking > volcanos? > > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=460949352 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic sensors From: "David A. Latsch" blottobear@.......... Date: Thu, 12 Oct 2000 20:11:41 -0600 Hi Doug, These are military seismic detectors used to monitor troop and vehicle movement along trails/roads. Similar units are available from Fair Radio and various surplus sources for much less. Dave Latsch Doug Crice wrote: > Does anybody recognize these "seismic sensors"? Since they come from > the area of Mt. Hood, might they be micro-earthquake gear for tracking > volcanos? > > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=460949352 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. Hi Doug,
These are military seismic detectors used to monitor troop and vehicle movement
along trails/roads. Similar  units are available from Fair Radio and various surplus sources
for much less.
Dave Latsch

Doug Crice wrote:

Does anybody recognize these "seismic sensors"?  Since they come from
the area of Mt. Hood, might they be micro-earthquake gear for tracking
volcanos?

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem &item=460949352
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

To leave this list email PSN-L-REQUEST@.............. with
the body of the message (first line only): unsubscribe
See http://www.seismicnet.com/maillist.html for more information.

Subject: wq sac format From: "Francesco" franuc@...... Date: Wed, 18 Oct 2000 23:20:01 +0200 Hi gang. I noted this problem in Winquake: when I save a file in sac_binary and review it, the file have lost = station inf and some other part of header. In fact, Sac id appear in = station form of "modify" men=F9, instead of....Rome, Los Angeles etc... In the last week I begin to use a dos program (Iaspei) to localize = regional event, that read sac format (ascii, also) input file. But, with = these files saved by WQ, it's impossible to run it fine, because it = don't recognize the sac-header (station ID and coordinates). The same = problem with ascii format (ascii-psn..?). It's right or it's a mistake of mine. Francesco, Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: wq sac format From: Larry Cochrane cochrane@.............. Date: Fri, 20 Oct 2000 14:39:52 -0700 Francesco, At 11:20 PM 10/18/00 +0200, Francesco wrote: >Hi gang. > >I noted this problem in Winquake: >when I save a file in sac_binary and review it, the file have lost station inf and some other part of header. In fact, Sac id appear in station form of "modify" menů, instead of....Rome, Los Angeles etc... You loss some information when you save a PSN file as a SAC file. This is because the SAC format does not have all of the fields that the PSN format has. The main fields that are missing are the comment and station name strings. > >In the last week I begin to use a dos program (Iaspei) to localize regional event, that read sac format (ascii, also) input file. But, with these files saved by WQ, it's impossible to run it fine, because it don't recognize the sac-header (station ID and coordinates). The same problem with ascii format (ascii-psn..?). If you have a SAC file that does work with the Iaspei program send it to me (in a private message) so I can see what the difference is between a file saved by WinQuake and one that can be read in by the program. -Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mountain top camera From: Jan Froom froom@............. Date: Mon, 23 Oct 2000 07:46:41 -0700 I have an opportunity to put a weather station and camera atop Loma Pretta (same Loma Pretta as the 89 earthquake). We have a view from Monterey to Santa Curz & Scotts Valley on the west and from San Jose to Gilroy on the east. Because it's scenery and not live action, I don't see the need for live video... but I would like to have high resolution And I'd like to download the image via a radio modem. Do any of you have any suggestions on type of camera to use.... or comments... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ebay seismographs From: BOB BARNS roybar@........ Date: Mon, 23 Oct 2000 21:54:00 -0400 Hi gang, Three items on ebay: 1. EG&G exploration seismograph 473114350 2. PS-1 Seismograph 475025972 3. Nimbus Industries Pocket Seis. 474875757 No. 3 is a mystery to me. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ebay seismographs From: david@............. (David Josephson) Date: Mon, 23 Oct 2000 19:33:34 -0700 (PDT) > > Hi gang, > Three items on ebay: > 1. EG&G exploration seismograph 473114350 I'll bet Doug Crice will be surprised to read that this unit, an ES-125 designed by him, "uses LSI technology" > 2. PS-1 Seismograph 475025972 > 3. Nimbus Industries Pocket Seis. 474875757 This is also a Doug Crice product. Properly adjusted, the LED readouts show the time from hammer pulse to first arrival, useful for some basic refraction surveys. > No. 3 is a mystery to me. > Bob Barns > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > -- David Josephson / Josephson Engineering / Santa Cruz CA / david@............. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ebay sensor From: BOB BARNS roybar@........ Date: Tue, 24 Oct 2000 20:24:52 -0400 Hi gang, ebay # 472860456 is a Kinemetrics SMA-1. Is this a seismograph? The auction ends 11/25 about 18:00 PDT. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ebay sensor From: The Lahrs johnjan@........ Date: Tue, 24 Oct 2000 18:41:50 -0600 The SMA1 is a strong motion unit that records on photographic film. It is set to trigger, usually at about .05 g, and then record for a set duration. Digital technology has made these instruments obsolete. John At 06:24 PM 10/24/00 , you wrote: >Hi gang, > ebay # 472860456 is a Kinemetrics SMA-1. Is this a seismograph? >The auction ends 11/25 about 18:00 PDT. >Bob Barns John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Special Pub 254 on it's way From: Charlie Rond rond@................ Date: Thu, 26 Oct 2000 07:01:36 -0500 Ted, Did you receive my check for $5 for a copy of Special Pub 254? >Some of you may have already received your copies of Interpretation of >Seismograms. --Charlie Rond -\/\--Public Seismic Network-Memphis http://www.ceri.memphis.edu/~rond/psn __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Apologies: Special Pub 254 on it's way From: Charlie Rond rond@................ Date: Thu, 26 Oct 2000 07:07:14 -0500 My apologies for sending this message - intended for Ted Blank - to the entire PSN list. I guess it was too early in the mornng. Ted, Did you receive my check for $5 for a copy of Special Pub 254? >Some of you may have already received your copies of Interpretation of >Seismograms. --Charlie Rond -\/\--Public Seismic Network-Memphis http://www.ceri.memphis.edu/~rond/psn __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: strain and tilt units From: ChrisAtUpw@....... Date: Sat, 28 Oct 2000 06:40:05 EDT In a message dated 18/09/00, sean@........... writes: > I have submitted an abstract to the AGU meeting regarding the new dynamic > broadband tiltmeter that senses pure tilt but is not sensitive to horizontal > acceleration as a seismometer is, so it can be used to record and > remove tilt noise from broadband horizontal seismic data. The current > resolution is 8.3 picoradians (10^-12). It readily records such earth tilt > noises as acoustic gravity waves (from storms) at 50 nanoradians (10^-9) > amplitude. (I will post the abstract on my web site later in the week.) Dear Sean-Thomas, Have you managed to finalise the tiltmeter details / disclosures yet please? I have visited your Website several times to try to get information on your exciting developments, but the tiltmeter section is still labelled "pending"..... Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: new seis. texts From: BOB BARNS roybar@........ Date: Sat, 28 Oct 2000 10:58:55 -0400 Hi gang, Physics Today mag. for Nov., 2000 has (pp56-57) two long reviews of new seismology text books. 1. "Principals of Seismology" by A. Udias $90 or $39.95 paper back. 2. "Intro. to Seismology" by PM Shearer, $74 or $30 paper back. Both are said to be very good. No. 1 is said to be more appropriate for 1st year graduate students and no. 2 is at a slightly lower level. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: BBT abstract for AGU From: sean@........... Date: Sun, 29 Oct 2000 15:03:17 -0600 (CST) Chris, I'm sorry that I never posted the AGU abstract. I still think that I can get much more done than reality allows. I used to be able to run a dozen projects at the ends of the earth, but my disabilities are now an unfortunate limitation. And then someone shared the two-week flu that is going around. My major effort in early October was to complete the preliminary technical report on the beam-balance tiltmeter: a very difficult effort to define the project from all the theoretical, mechanical, and electronic aspects, as well as to present some very initial data. The report runs 60 pages of text and 40 of figures, and none of it is in a condition to mark up to HTML. I have sent it to those who I thought could provide a really critical review, but so far I have only got back "nicely written ... as far as I got ... about page 5". So I guess that if it was complicated for me to write, maybe it IS unreadable. I had hoped for (and they were anxious to provide) good criticism from ASL (the national Albuquerque Seismological Lab.) but they are in the process of relocating because their lease on the reservation went up by over 10X. They moved their servers, etc, on Oct. 18. I don't know the fate of the ANMO test site (a very quiet deep tunnel) where we were planning on testing the new tiltmeter. (So I am setting up a side-by-side test with an STS-2 with an 8-channel, 24-bit digitizer in my remote vault.) Another problem came up last week when the leaf-spring vertical seis in the basement here bonked; details next. Here is the AGU abstract. I have submitted it with Dr. Mitchell as a second author and presenter, since I don't think I will be able to attend; but I am looking to attend the SSA meeting in SFO in April with new data. Regards, Sean-Thomas ________________________________________________ An abstract for the fall 2000 AGU meeting. A Beam-Balance Broadband Tiltmeter That is Insensitive to Horizontal Acceleration. Sean-Thomas Morrissey (sean@............ Brian J. Mitchell (mitchell@............ (Dept. of Earth and Atmospheric Sciences, St.Louis University, 3507 Laclede; St. Louis MO, 63103; 314 977 3129; A new beam-balance tiltmeter has been developed that does not respond to horizontal ground movement. Since all horizontal seismometers are also tiltmeters they are sensitive to tilt, especially at longer periods, and seismic data can be compromised in the period range of 20 to 3000 seconds. The most important noise source in the horizontal data is tilting of the pier, mostly due to barometric loading. But all tiltmeters, up to now, are also seismometers, (ie. they are sensitive to horizontal translation), so can not be used to separate tilt noise from seismic signals. Our new beam balance tiltmeter does not respond to horizontal acceleration because the masses at each end of the horizontal beam are suspended through the exact center of mass. This system is inherently unstable, so broadband feedback is used to control it. With appropriate feedback, the beam remains relatively horizontal when the base is tilted, and the output is the relative motion at the displacement detector. There is no rotation or output when the base is translated horizontally along the axis of the beam. The beam-balance tiltmeter is designed with separated lead masses mounted in an aluminum bar that is suspended exactly at the center of mass of the horizontal beam with a new low torque hinge flexure. The center of mass is trimmed by a unique vertical mass centering adjustment above the flexures. Displacement transducers and compact force feedback coils with rare-earth magnets are placed at both ends of the beam. Three sensors have been assembled as "proof of concept" prototypes. One instrument is operating at station CCMO, near Saint Louis University, and data from it are being digitized. Another is on a table and can be used to demonstrate that tilt can be separated from horizontal acceleration by simply sliding it horizontally. The static or DC tilt sensitivity of the prototype is about 120 millivolts per microradian, and the resolution is better than 0.1 nanoradian. Initial comparisons using data generated by large quakes on the horizontal components of nearby broadband seismic stations (18 km distant) show that the response to horizontal acceleration is reduced by a factor greater than 1000 while maintaining the equivalent tilt sensitivity of the seismometer. Ideally, the noise recorded in the tiltmeter output will exactly emulate the tilt noise from the seismometer, at least in the flat portions of their broadband velocity response. The success of this new instrument has a tremendous implications for broadband stations in all regions of the world where tilting from barometric, thermal, hydrologic, etc., effects may limit the usefulness of the horizontal data. ____________________ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: epoxied hinges bonk From: sean@........... Date: Mon, 30 Oct 2000 17:02:14 -0600 (CST) Here is an update on the fastening of the hinges for the STM-8 leaf spring vertical seis: Epoxying the hinges to the frames is not reliable in the long run. The seis here went bonk in the night and I assumed that it was simply out of the capture range of the feedback because of the seasonal temperature changes. But the remote zero did nothing, and investigation showed that two of the flexure strips on one side of the hinge had become unglued. In the initial ideas and design of the instrument, I thought that gluing the flexures would be a reliable simplification of the design, and it has survived for several years even on the original prototype. The epoxy surface preparation was limited to sanding with 400 grit paper. But any failure in something that has to run unattended for many years is not acceptable, so epoxying the hinge flexures is probably not a good idea in the long run; it still might be if proper surface preparations are made (McMaster has pages of adhesive primers). And indeed, the flexures that remained glued had to be forcibly peeled from the frame members. But one of the major VBB sensor companies has also had problems with adhesives peeling loose after several years that jammed the mass. So the ultimate long term reliability seems to favor clamped flexures, even though this involves many additional parts with the increased contribution of micropositioning noise from thermal and mechanical stress. It is possible that using a slow set acrylic adhesive or even Locktite under the clamps might reduce these effects. To replace the flexures on the STM vertical (as shown in the web site drawing) I used the same 0.005" by 3/4" wide phosphor bronze strapping, but with the full 3/4" width on each side of the 3/8" center section that is the actual hinge area (the epoxied flexures were simply straight 3/8" wide strips). I used a standard paper punch to make 1/4" large clearance holes for the 6-32 fastening screws; a good punch will make a clean, minimally stressed cut, and is also used to shape the 3/8" wide center flexing section. The aluminum brackets (1 1/2" x 1 1/2" x 1/8" thick angles 4 1/2" long as in the drawing) are drilled and tapped (with light oil) for the 6-32 screws which are 3/8" and 1" back from the hinge corner. The clamping bars are made from 1/2" wide by 1/16" thick brass bar (ACE hardware) strips cut 1 1/4" long, and filed to a shallow angle at the inside end. The 3/16" screw holes are 5/16" and 15/16" back from the inside end. After cutting and drilling, these are carefully deburred and rounded at the edges to provide a uniform clamping surface. To assemble the hinge, the two brackets are clamped in the X shape using an L bracket in the center; the hinge corners are spaced 0.005" apart each way using the hinge stock under each side of the L bracket and crossing through the center of the assembly (where the hinges themselves cross, the bracket corners are flattened by 1/8" so that the actual flexing area is untouched). The 4 flexures, 8 clamp bars, 16 SS screws and lockwashers are all loosely assembled and squared up before being gradually tightened so as not to torque the flexures. The inside angled edge of the brass clamps is aligned with the outside edge of the flattened section of the bracket corner in the flexure area, with the slightly longer side against the flexure strip. The two flexures should not touch. This should all be clarified by a drawing of the details. And a picture is worth 10^3 words next time I play with the camera and the scanner. Actually, I am inclined to redesign the whole seismometer to about 1/2 the size using the soldered box flexures and the bought parts coil/magnet assembly I have previously described. regards, Sean-Thomas ____________________ ____________________ \ / ----- ----- ____________________/ \____________________ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: epoxied hinges bonk From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Mon, 30 Oct 2000 18:35:17 -0500 If you look at my website, I used clamping bars to hold hinges. I haven't had time to get back to the VBB, maybe this winter!! sean@........... wrote: > Here is an update on the fastening of the hinges for the STM-8 > leaf spring vertical seis: -- Rex Klopfenstein, Jr. Bowling Green, OH KC8PFP rklopfen@......... http://www.wcnet.org/~rklopfen __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: epoxied hinges bonk From: ChrisAtUpw@....... Date: Wed, 1 Nov 2000 08:01:07 EST In a message dated 30/10/00, sean@........... writes: > Epoxying the hinges to the frames is not reliable in the long run. > The seis here went bonk in the night and investigation > showed that two of the flexure strips on one side of the hinge had > become unglued. > In the initial ideas and design of the instrument, I thought that > gluing the flexures would be a reliable simplification of the design, > and it has survived for several years even on the original prototype. > The epoxy surface preparation was limited to sanding with 400 grit paper. > But any failure in something that has to run unattended for many years is > not acceptable; it still might be if proper surface preparations > are made (McMaster has pages of adhesive primers). And indeed, the > flexures that remained glued had to be forcibly peeled from the frame > members. But one of the major VBB sensor companies has also had problems > with adhesives peeling loose after several years that jammed the mass. Dear Sean, No adhesive is perfect, but epoxies can give excellent bonds if you allow for their limitations. They a) have a relatively low peel strength b) do not like water one little bit and c) need to be fully cured. You can usually design joints to increase the resistance to peel forces. This could be done for the hinges by sticking the foil onto the 1.5" L beam and then sticking a cover plate twice the foil width over the top, to give an overlapping sandwich construction. It is not generally realised how seriously epoxy joints are weakened by damp surfaces. The adhesion may be markedly improved by heating the materials to be joined in an electric oven at 150 C for half an hour, which removes most of the surface adsorbed water. You remove the material from the oven and put adhesive on while it is still hot. It may then be rapidly contact cooled and the joint fully assembled while still warm, but before the glue has set. Water contamination is especially noticeable when gluing ceramics and glass. You can also use an electric blower / paint stripper, but the temperature control may be more difficult. Many epoxies will develop stronger characteristics if they are cured at a raised temperature (maybe 60 C?) after they have 'set' at room temperature. Do check the specification sheets. Select a low curing temperature from the range recommended to minimise cold joint stresses. I hope that these observations may be of some help in turning the 50% success rate into 100%! Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: epoxied hinges bonk From: barry lotz gbl@....... Date: Sat, 04 Nov 2000 05:55:05 -0800 Sean Thomas 2˘ I have not been running my SMT8 style verticals for very long so the hinge contition has not had adequate history. I use an additional brass clamp ~.125" from the hinge(just enough to allow clearance from the perpendicular clamp. The hope was that it would take most of the tension. Aluminum has an oxide coating at the surface (which makes it hard to weld in an air environment). Could this maybe contribute to the bond issue. From what I've heard, if one sands aluminum that the oxide forms almost immediately. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: epoxied hinges bonk From: BOB BARNS roybar@........ Date: Sat, 04 Nov 2000 13:34:13 -0500 Barry, Yes, aluminum gets an oxide film after sanding or any other cutting operation. However, epoxy should bond to the oxide just as well as to bare metal, perhaps better. ALL surfaces in an ordinary ambient (room temperature) are covered with a layer of water from 1 to several molecules thick. One of the rules for making an adhesive work is that it is necessary for the adhesive to wet the surfaces. Epoxy and water don't mix and so epoxy will not wet a wet surface. Chris Chapman's recent discussion on this net suggests ways of improving adhesion. Raising the temperature can do a pretty good job of reducing the adsorbed water layer. Bob Barns barry lotz wrote: > > Sean Thomas > 2˘ I have not been running my SMT8 style verticals for very long so the > hinge contition has not had adequate history. I use an additional brass clamp > ~.125" from the hinge(just enough to allow clearance from the perpendicular > clamp. The hope was that it would take most of the tension. Aluminum has an > oxide coating at the surface (which makes it hard to weld in an air > environment). Could this maybe contribute to the bond issue. From what I've > heard, if one sands aluminum that the oxide forms almost immediately. > Regards > Barry > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Note on a diamagnetics item From: meredith lamb mlamb1@.......... Date: Sat, 04 Nov 2000 14:42:20 -0800 Hi all, Although diamagnetics isn't a strong interest item, I note that Forcefield/Wondermagnet now has in stock some diamagnetic graphite blocks for sale at a very reasonable price, per my own past experience with a variety of graphite/bismuth. Its hard to find "good" diamagnetic graphite when going any home brew or salvage/surplus route. The size shown is not commonly found anywhere. The pictures at this site are very good, and in the route illustrated offers a very low cost visual observer only approach to this phenomena. : http://www.wondermagnet.com/dev/magnet36.html Off the bat, I'd recommend the little gold plate cube, it has a better field strength, and is available there also. Its visually easier to see movement changes. My own N-S experimental Hall sensor geomagnetic/crude seismo, is still in operation at this time....but for seismic purposes, it is only a curiosity and non-effective approach....that I tried....and don't recommend for seismic use. Fun to try though. I use a much more expensive grade of graphite mainly for long term "floatation" temperature variation stability. The URL does lead to other pictures that maybe of interest and also to my own linked reference amateur site, as well as other related/non-related subjects. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: help] From: Wayne Abraham J73WA abrahamw@........ Date: Sun, 05 Nov 2000 17:33:23 -0400 Hello gang I received this email from someone in the Dominican Republic. Can any of you help him? I do not know if he has subscribed to this list so pleas reply directly to his email address. Wayne -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica mailto:abrahamw@........ http://dominicapsn.freeyellow.com/ Hi Mr Abraham, I am part of a group that are studying the posibility to install a = seismic network across the dominican republic, I have already a = quotation for the equipment needed, we are locating the seismic points = across the country, but I need to know: 1.- Transmitter/Receiver operation range (in km). Because in the = quotation the Transmitter/Receiver range is 20miles(32km) 2.- How do you performe the frequency exploration (equipment needed for = this task) between a station an the central. 3.- Can I use a remote station also as a repeater. Please I need your comments on this issue, all the information will be = welcome, and if you can refer someone will be very nice. Thanks for all your help, Eugenio Fajardo
Hi Mr Abraham,
 
I am part of a group that are studying the = posibility to=20 install a seismic network across the dominican republic, I have already = a=20 quotation for the equipment needed, we are locating the seismic points = across=20 the country, but I need to know:
 
1.- Transmitter/Receiver operation range (in km). = Because in=20 the quotation the Transmitter/Receiver range is = 20miles(32km)
 
2.- How do you performe the frequency exploration = (equipment=20 needed for this task) between a station an the central.
 
3.- Can I use a remote station also as a=20 repeater.
 
Please I need your comments on this issue, all the = information=20 will be welcome, and if you can refer someone  will be very=20 nice.
 
Thanks for all your help,
 
Eugenio Fajardo
Subject: Re: help] From: "John Krempasky" johnk@....... Date: Sun, 5 Nov 2000 17:53:22 -0500 ----- Original Message ----- From: "Wayne Abraham J73WA" To: "PSN-L Mailing List" Sent: Sunday, November 05, 2000 4:33 PM Subject: [Fwd: help] > Hello gang > > I received this email from someone in the Dominican Republic. Can any of > you help him? I do not know if he has subscribed to this list so pleas > reply directly to his email address. > > Wayne > > -- > Wayne Abraham > 1430 Rodney Street > Portsmouth, Dominica > > mailto:abrahamw@........ > http://dominicapsn.freeyellow.com/ > Dominica isn't the Dominican Republic..it's a tiny island in the Lesser Antilles :-) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 1 sec Vertical Seismometer Needed From: Jeff Batten jeff.batten@........ Date: Tue, 07 Nov 2000 10:22:08 -0800 Hello, Does anyone have a used Ranger or L4-C seismometer that they want to sell. I have a friend that is looking to buy one if the price is right. Thanks Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 1 sec Vertical Seismometer Needed From: meredith lamb mlamb1@.......... Date: Tue, 07 Nov 2000 11:56:53 -0800 E-Bay has a present auction on a Ranger seismo. Item # 486684345. This is a re-listing of # 430096282. I checked with the seller and the person claims the prior high bidder never sent the $490. Why other high bidders weren't approached is unknown? The unit is sold as is....and the coil/s condition is unknown also. Think the winning bid could also get high again. Biggest concern....it may not be in workable condition?? Jeff Batten wrote: > Hello, > > Does anyone have a used Ranger or L4-C seismometer that they want to sell. > > I have a friend that is looking to buy one if the price is right. > > Thanks > > Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Paired aftershocks From: "Alan and Jocelyn Munro" mjpad@.............. Date: Wed, 8 Nov 2000 19:30:45 +1300 Following the Fiordland MI 6.2 quake in South Island New Zealand I have recorded 18 aftershocks from the area. One of my school students noted that many of the aftershocks occured as pairs ( about 5 pairs) separated by about 1 minute. See example of 5 Nov. Has anyone else noticed this phenomena and what could be causing this. Thank you Alan Munro Invercargill Subject: Could someone please evaluate this site? From: "Stacey S. Martin" 9point1@....... Date: Wed, 8 Nov 2000 21:02:14 +0530 Hi,=20 My name is Stacey Martin, a quake-crazy 19 year old from Pune, = India. I have set up a website for earthquakes in South Asia. . It does = not have any wave form data and neither am I able to record seismic = activity*. However, I have tried to put together information on the = region's seismicity, great earthquakes, tsunamis and also historical = activity. I also try and maintain a current activity page, where recent = events are listed as reported by local stations or the NEIC. I have got = the information from various sources and have kind of customized it to = suit the region. Could someone please check out this site and tell me = what you think? I have had some visitors so far and there has hardly = been any feedback.=20 =20 The URL is http://www.geocities.com/stasertin =20 Thanks, Yours sincerely, Stacey S. Martin * I wanted to build and run a seismograph but it is really impossible as = I live on the 2nd floor of a 6 storey apartment building with an = extremely busy avenue running just 100 meters away.
Hi,
    My name is Stacey = Martin, a=20 quake-crazy 19 year old from Pune, India. I have=20 set up a website for earthquakes in South Asia.  . It does not = have any wave=20 form data and neither am I able to record seismic=20 activity*. However, I have = tried to put=20 together information on the region's seismicity, great earthquakes, = tsunamis and=20 also historical activity. I also try and maintain a current activity = page, where=20 recent events are listed as reported by local stations or the NEIC. I = have got=20 the information from various sources and have kind of customized it to = suit=20 the region. Could someone please check out this site and tell me = what you=20 think? I have had some visitors so far and there has hardly been any = feedback.=20
 
The URL is = http://www.geocities.com/stas= ertin
 
Thanks,
Yours sincerely,
Stacey S. Martin
 
* I wanted to build and run a = seismograph but it is=20 really impossible as I live on the 2nd floor of a 6 storey apartment = building=20 with an extremely busy avenue running just 100 meters=20 away.
Subject: Re: Could someone please evaluate this site? From: bharath bharaths@............ Date: Wed, 08 Nov 2000 11:14:02 -0500 hi, Stacey Thankyou for sending me the link to your we site. i am not into earthquakes, i work for a company that manufactures enclosures, and i have an interest in computer furniture that is cable of seismic vibrations. i think you have a really nice interactive site, i would be interested to know why you build this site. regards bharath ----- Original Message ----- From: Stacey S. Martin To: psn-l@.............. Sent: Wednesday, November 08, 2000 10:32 AM Subject: Could someone please evaluate this site? Hi, My name is Stacey Martin, a quake-crazy 19 year old from Pune, India. I have set up a website for earthquakes in South As ia. . It does not have any wave form data and neither am I able to record seismic activity*. However, I have tried to put toge ther information on the region's seismicity, great earthquakes, tsunamis and also historical activity. I also try and maintain a current activity page, where recent events are listed as reported by local stations or the NEIC. I have got the information f rom various sources and have kind of customized it to suit the region. Could someone please check out this site and tell me wha t you think? I have had some visitors so far and there has hardly been any feedback. The URL is http://www.geocities.com/stasertin Thanks, Yours sincerely, Stacey S. Martin * I wanted to build and run a seismograph but it is really impossible as I live on the 2nd floor of a 6 storey apartment buil ding with an extremely busy avenue running just 100 meters away.
hi, Stacey
Thankyou for sending me the link to your we site.
i am not into earthquakes, i work for a company that manufactures enclosures, and i have an interest in computer furniture that is cable of seismic vibrations.
i think you have a really nice interactive site, i would be interested to know why you build this site.
 
regards bharath
 
----- Original Message -----
Sent: Wednesday, November 08, 2000 10:32 AM
Subject: Could someone please evaluate this site?

Hi,
    My name is Stacey Martin, a quake-crazy 19 year old from Pune, India. I have set up a website for earthquakes in South Asia.  . It does not have any wave form data and neither am I able to record seismic activity*. However, I have tried to put together information on the region's seismicity, great earthquakes, tsunamis and also historical activity. I also try and maintain a current activity page, where recent events are listed as reported by local stations or the NEIC. I have got the information from various sources and have kind of customized it to suit the region. Could someone please check out this site and tell me what you think? I have had some visitors so far and there has hardly been any feedback.
 
 
Thanks,
Yours sincerely,
Stacey S. Martin
 
* I wanted to build and run a seismograph but it is really impossible as I live on the 2nd floor of a 6 storey apartment building with an extremely busy avenue running just 100 meters away.
Subject: Re: Paired aftershocks From: "Ian Greenwood" judgedred@.............. Date: Wed, 8 Nov 2000 19:50:39 -0000 Can't open the attachment, what is the application that should be used? Judgedred UK ----- Original Message ----- From: Alan and Jocelyn Munro To: PSN-L Mailing List Sent: Wednesday, November 08, 2000 6:30 AM Subject: Paired aftershocks > Following the Fiordland MI 6.2 quake in South Island New Zealand I have > recorded 18 aftershocks from the area. One of my school students noted that > many of the aftershocks occured as pairs ( about 5 pairs) separated by about > 1 minute. See example of 5 Nov. > Has anyone else noticed this phenomena and what could be causing this. > > Thank you > > Alan Munro > Invercargill > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Paired aftershocks From: "David A. Nelson" davenn@........... Date: Thu, 9 Nov 2000 08:01:24 +1100 At 19:50 08/11/00 -0000, you wrote: >Can't open the attachment, what is the application that should be used? > >Judgedred >UK > Winquake is the program to use get it at http://www.seismicnet.com have fun Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 13 Monash Rd., Gladesville, (Sydney) 2111 NSW, Australia http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Paired aftershocks From: John Hernlund hernlund@............ Date: Wed, 08 Nov 2000 15:23:08 -0800 Alan and Jocelyn Munro wrote: > Following the Fiordland MI 6.2 quake in South Island New Zealand I have > recorded 18 aftershocks from the area. One of my school students noted that > many of the aftershocks occured as pairs ( about 5 pairs) separated by about > 1 minute. See example of 5 Nov. > Has anyone else noticed this phenomena and what could be causing this. > Alan Munro > Invercargill Alan, This sounds quite interesting. It would be cool to see a plot of the time line of these aftershocks to put it all into perspective. Also, if the locations are available it would be cool to see "pairs" plotted on a map (maybe distinguishing different pairs by a given color or symbol). This almost seems like a case for triggering...if that were so then I might guess that the second aftershock in the pair sequence was occurring in a very focused area. If you have the data, but not the plotting tools, maybe you can send the data to me and I can throw together a couple of gifs to post on the web. Cheers! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: humor From: Phil Giannini pgiannini@........ Date: Thu, 09 Nov 2000 13:33:44 -0800 Hi Gang, Found this little tid-bit while poking around on the net. Thought you'd all get a kick out of it. http://www.saturn-ca.com/california.html Regards, Phil __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VHF telemetry From: sean@........... Date: Thu, 9 Nov 2000 15:32:57 -0600 (CST) Eugenio, Has anyone responded regarding your questions about radio telemetry? Over the years I have been able to operate several RF telemetry networks in difficult situations with quite long distances and many repeaters. The "standard" station is a 1 to 6 channel seismic pre-amp/VCO unit with FM audio carriers feeding a narrowband FM (5khz) VHF transmitter with 100 milliwatts (0.1 watt) power operating on 50 milliamps at 13 volts from a 1100 Ampere-Hour Zinc-Carbon-Air battery pack for up to two years. The frequencies are from 165 to 175 Mhz, with 5-element Yagi antennas with 6 db gain at each end of the link. The largest network has been the 36 station network in the New Madrid region. We could manage distances up to 70 km with the station antenna about 10 meters up in a sturdy tree and the receive antennas 30 meters up a cable TV tower. The terrain there is very flat, but we did use the highest hills as remote station sites. Because we had only 12 RF frequencies to use, the layout was critical so we wouldn't interfere with our own signals. In the Aleutians, the mountainous islands with no trees made transmission easy from 3 meter antenna masts, again with some 50 km links. To see its extent, get your map of Alaska and look for the islands Adak (the central station), G. Sitkin. Umak, Kagaglaska, Tanaga, and Kanaga, with repeaters on SE Tanaga and the Yakak peninsula at the SW corner of Adak. In the Aegean network, I put a station on western Crete transmitting to Milos and repeating to the SE Polyponeseus and then repeating to Athens. You might have trouble finding maps for the network from Nurek to Dushanbe in Tadjikistan and at Totugul in Kirgisia, but again we used high hills in the relatively barren Tien Shan and Hundu Kush, with 2 meter pipe masts for the antennas to transmit as much as 100 km. Our highest station was at 4100 meters. The problems there were that the Russian "air-cell" batteries were very unreliable, and the nomadic horsemen would lasso the antenna and pull it down. Regarding the performance of a low power VHF radio link for narrowband seismic telemetry: You can estimate the effectiveness of a VHF link over any given terrain knowing the transmitter power, the antenna gains, and the receiver threshold for a given "fade margin", the percentage of time that the signal received will be too weak to use. And then you can throw a mountain in the way and estimate the added loss. Also be mindful that VHF refracts downward in the lower atmosphere, increasing the propagation over the visual horizon as if increasing the earths' radius by 1/3. This increase in distance is often estimated when plotting the profile of the propagation path by using 4/3 radius profile paper, or a single curve representing the "flattened" earth. Assume that your typical VHF receiver unsquelches at a signal of 1 microvolt, at 50 ohms, which is -137 db. (the db power ratio is 10*log(power[in watts] referred to 1 watt (0 db)). A 0.1 watt transmitter puts out -10 db to the antenna. The yagi antennas at each end improve this by +12 db. The propagation path loss is estimated by A = 37 + 20*log(f) + 20*log(d), where f is Mhz and d is miles. So if f is 170mhz (+44.6) and d is 50 miles (80km) (+33.97), the path loss is 115.58 db. So we get -114 db to the receiver, for a fade margin of (-10 +12 -116) -(-137) or about 23 db, which is a relatively strong signal. At 20 db, the signal reliability is 99%, but at only 10 db, it is 90%, and subject to atmospheric variables, like inversions that refract it right out to space. For seismic telemetry minor fades and bursts of static can usually be handled by the data discriminator if the audio carrier filter is properly tuned and the active squelch is adjusted properly. Very rarely do these trash a seismic event since they only last several seconds. Bear in mind here that the "line of sight" constraint for VHF propagation is for the most part wrong: the antenna is not putting our a "beam" until the frequencies go above 1 GHZ, but rather is launching an electromagnetic wave in free space. An object in the way is a scatterer, not a brick wall, as long as it resides near the center 1/3 of the propagation path. At Adak, we transmitted directly toward a mountain range in the center of the path from the the station and repeater on Yakak peninsula. If we throw a mountain in the way, its addition to the path loss can be estimated using nomographs. A "knife edge" peak near the center of a 50 km propagation path will cause an additional loss of -10 db if it rises 50 meters above the 4/3 curve. If the mountain is 100 m high, the loss is -14, and if 200 m high, the loss is -18. These losses are highly dependent on the geometry of the mountain, and may be twice these values. But I have found that a profile grazing within about 30 m of a ridge top will add a loss of about -10db, and a conical peak in the path is of little concern. So what if the fade margin is less than 10db?: (and some things I have done) 1: The received signal may be full of static, which is often largely eliminated by the narrow-band carrier filter of the seismic discriminator. 2: Some receivers specify a threshold of 0.5 microvolt, or -143 db, or about a 6 db improvement. Note that this is an optimal performance value. 3: The optimal consistent performance of both transmitters and receivers assumes that they stay bone dry (ie. in a monitored, desiccated sealed container), since humidity will change the geometry of the tuning coils. 4: Many transmitters can be "peaked up" for an increase in power to 0.2 watt, for an increase of +6 db, at the expense of battery longevity. (In the Aleutians, we needed 2 years of power from the battery pack, limiting our total station current to 65ma (at 12.6 volts)). 5: Receivers can be fine tuned for a given link to lower the noise by 10db or more. I have packed a portable oscilloscope 300 feet up cable TV towers to make an otherwise marginal signal strong and reliable. This, or course, has to be repeated if either the transmitter or receiver are changed. Prior to deployment, pre-tuning each radio link in the lab using a crystal frequency standard (10^-6 accuracy) can make a big difference. 6: Arrays of antennas (at the receive site) can improve the signal by 10 to 20 db, but add cost and complexity. 7: It is best to carefully plan station sites beforehand, but sometimes relocating a station to a better/higher location can do wonders. Changes in the seismic array geometry by several kilometers have little impact on the seismic event location accuracy, but a large impact on site noise and the reliability of the radio link. I hope these comments are helpful. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: humor From: Doug Sutherland doug@............. Date: Thu, 9 Nov 2000 13:31:36 -0800 Phil wrote: >http://www.saturn-ca.com/california.html I like it! It even makes my linux box shake :) It would be more authentic if the screen would fill in with haze while the ground shakes. -- Doug __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Digital Seismic drum From: Arie Verveer ajbv@............ Date: Sun, 12 Nov 2000 04:47:35 -0500 Hi, At the moment I'm running an early beta test for a digital drum recorder. It automatically loads in the files from the "SDR" computer for one day then performs some digital filtering and creates a daily drum record. (Gif format). This is then FTP'ed to my web site for general viewing. If you are interested in the viewing the daily recordings from Western Australia then : http://www.iinet.net.au/~ajbv The Induction magnetometers readings are also displayed. These display's are updated daily between 1:00 - 1:30 UTC. I do expect some some problems by hopefully they are not too big. The Link to the Web site is always a problem. Cheers Arie. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Digital Seismic drum From: "Francesco" franuc@...... Date: Sat, 11 Nov 2000 19:52:58 +0100 Hello Arie. Relevant idea and good realization. From some weeks I and Mauro Mariotti, of PSN-Italy, are interested in = the same features.=20 I send an e-mail to Larry to know a right way to visualize on web the = traces of the stations from SDR. Actually the only system is to replay = from Winquake a lot of time of record, then it save automatically into a = gif format and at least put it in the web server. To do this action we = have realized a batch file that, every * minutes generate a replay file = into sdr replay directory and save a gif file. Not too complicated. But the problem is that so doing, we show by internet a winquake trace = and window, with a Y view not resizable and one row only... I wish to view all the traces of the day, or the traces recorded within = a certain point. Almost the same thing of your software....... To send the gif file into web server we will use a freeware software = (watchcam) that automatically create an html page with the immage, = connect with our ISP and upload the right directory every 1 (or + or = -)hour. Please, can you tell me more information about your program? Regards Francesco Nucera - Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Digital Seismic drum From: "Francesco" franuc@...... Date: Sat, 11 Nov 2000 19:52:58 +0100 Hello Arie. Relevant idea and good realization. From some weeks I and Mauro Mariotti, of PSN-Italy, are interested in = the same features.=20 I send an e-mail to Larry to know a right way to visualize on web the = traces of the stations from SDR. Actually the only system is to replay = from Winquake a lot of time of record, then it save automatically into a = gif format and at least put it in the web server. To do this action we = have realized a batch file that, every * minutes generate a replay file = into sdr replay directory and save a gif file. Not too complicated. But the problem is that so doing, we show by internet a winquake trace = and window, with a Y view not resizable and one row only... I wish to view all the traces of the day, or the traces recorded within = a certain point. Almost the same thing of your software....... To send the gif file into web server we will use a freeware software = (watchcam) that automatically create an html page with the immage, = connect with our ISP and upload the right directory every 1 (or + or = -)hour. Please, can you tell me more information about your program? Regards Francesco Nucera - Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: Digital Seismic drum From: Arie Verveer ajbv@............ Date: Sun, 12 Nov 2000 03:28:25 -0500 Hello Francesco and Others, I wrote the program called "drum.exe" that requests data files from the "SDR" logging computer and then convert these binary data files into a "GIF" format file, report. The converted data can be digitally filtered , and automatically or manual scaled. The report can be "yesterdays" data or an update of today's data. Its operation depends on an external "scheduling" program, which launches this program at, predetermined times. This form of operation allows for greater flexibility. As the "scheduling" program may be specific program, a server "cgi" request and so on. I use WinSchedular to launch the program and AutoFTP to send the generated "GIF" reports to two web sites. You see, my station is some 11 kilometres from home. Anyhow you might want to check out Charlie's site at http://elfrad.com for an example of the "today's" version of the program. The shortest "SDR" time sequence is 120 minutes and the longest is 720 minutes. All the parameters are kept in a "*.ini" file associated with the program. It contains all the directory locations, file names, low pass, high pass, notch, band pass filter settings, display scale and so on. At the moment the code is being beta tested. It seems there may be some small interest in the program, but I'll need to talk to Larry and Charlie Plyler before I release the program freely. The "SDR" file structure is Larry's and the code probably wouldn't have been written this year without Charlie's interest in the magnetic data. So if all goes well you and any "PSN" members are welcome to the program. Remember for it to run in an automatic mode you need a networked computer to the "SDR" logging computer. You can manually load the "SDR" files and use the program to generate a report but that's labour intensive. This program is only a Helio-plot of the data not an analysis program. I hope this is helpful. If you or a PSN member, sill want the program, Email me at: ajbv@............ and then I'll approach the participants for approval. Cheers Arie PS: I write terrible documentation: > Relevant idea and good realization. > >From some weeks I and Mauro Mariotti, of PSN-Italy, are interested in the same features. > I send an e-mail to Larry to know a right way to visualize on web the traces of the stations from SDR. Actually the only syst em is to replay from Winquake a lot of time of record, then it save automatically into a gif format and at least put it in the web server. To do this action we have realized a batch file that, every * minutes generate a replay file into sdr replay direct ory and save a gif file. Not too complicated. > But the problem is that so doing, we show by internet a winquake trace and window, with a Y view not resizable and one row on ly... > I wish to view all the traces of the day, or the traces recorded within a certain point. > Almost the same thing of your software....... > > To send the gif file into web server we will use a freeware software (watchcam) that automatically create an html page with t he immage, connect with our ISP and upload the right directory every 1 (or + or -)hour. > > Please, can you tell me more information about your program? > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Drum + AutoFFT Software release From: Arie Verveer ajbv@............ Date: Tue, 14 Nov 2000 06:45:36 -0500 Hi, This may be of interest. I've placed the programs "Drum" and "AutoFFT" on my web site: http://www.iinet.net.au/~ajbv (Near the bottom of the page) Feel free to download them. Each package contains the program and instructions. "Drum" makes a plot of the days recordings and "AutoFFT" does bulk FFT's on PSN files. Also within "Drum" is a bit of code that requests files from the "SDR" logging computer. Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Drum + AutoFFT Software release From: Doug Sutherland doug@............. Date: Tue, 14 Nov 2000 03:42:40 -0800 Arie Verveer wrote: > "Drum" makes a plot of the days recordings and "AutoFFT" > does bulk FFT's on PSN files. Speaking of FFTs, in my quest for more "squiggly lines" I am playing with an electroencephalograph (EEG) that was designed in the same spirit as Larry's quake system. The specs are public and anyone can build it, or a complete system can be purchased. Interestingly, most of the tech concepts are the same including A/D conversion and FFT. But obviously that data interpretation is a completely different story. The EEG uses electrodes on my scalp to listen for different brain wave activity in the delta, theta, alpha, and beta ranges. Check it out: http://www.brainmaster.com and http://www.brainm.com -- Doug __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Drum + AutoFFT Software release From: Doug Sutherland doug@............. Date: Tue, 14 Nov 2000 03:42:40 -0800 Arie Verveer wrote: > "Drum" makes a plot of the days recordings and "AutoFFT" > does bulk FFT's on PSN files. Speaking of FFTs, in my quest for more "squiggly lines" I am playing with an electroencephalograph (EEG) that was designed in the same spirit as Larry's quake system. The specs are public and anyone can build it, or a complete system can be purchased. Interestingly, most of the tech concepts are the same including A/D conversion and FFT. But obviously that data interpretation is a completely different story. The EEG uses electrodes on my scalp to listen for different brain wave activity in the delta, theta, alpha, and beta ranges. Check it out: http://www.brainmaster.com and http://www.brainm.com -- Doug __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: seismograph calibration? From: "David Saum" DSaum@............ Date: Tue, 14 Nov 2000 17:07:31 -0500 I read Bob Barns' 1996 article about seismograph calibration and I wonder if there is not a much simpler method that does not require any special equipment. Suppose you just take the damping off a Lehman pendulum and give it a little shove. It will begin to oscillate and if you know the period and the amplitude then you can calculate the peak velocity in nm/s. Then you read the peak value from your ADC and that allows you to compute the velocity sensitivity of your seismograph in nm/s per bit. By observing your backgraound noise level in bits during normal damped operation you can convert it to nm/s. Or am I making a stupid mistake? And what is a good value for sensitivity and background noise level? When I do the tests above, it looks like I have a sensitivity of about 120nm/s/bit and my noise level is about +/- 3. I have a 16 bit ADC so should I crank up the analog gain a tad? The reason I am trying to calibrate my Lehman is that I just got it working and I can not figure why it detects some quakes well and others poorly. I am comparing my results with those posted on seismicnet. Especially the results from Herndon, VA which is just a few miles away from me at Bailey's Xroads, VA. I am trying to figure out whether I need more gain or is my location on a office building basement slab next to a busy street just too noisy? TIA for any help, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: seismograph calibration? From: "Larry Conklin" lconklin@............ Date: Tue, 14 Nov 2000 17:22:13 -0500 By any chance are you the same Dave Saum that used to work for GE in Syracuse about 15 years ago? The one I knew migrated to somewhere in Va, I think. Hope you get some good answers to your question. I too have been trying to get a handle on whether my typical background is just noisy or really really noisy. It would also be interesting to see some FFTs of "typical" background. Larry Conklin lconklin@............ ----- Original Message ----- From: "David Saum" To: Sent: Tuesday, November 14, 2000 5:07 PM Subject: seismograph calibration? > I read Bob Barns' 1996 article about seismograph calibration > and I wonder if there is not a much simpler method that does > not require any special equipment. > > Suppose you just take the damping off a Lehman pendulum and > give it a little shove. It will begin to oscillate and if you > know the period and the amplitude then you can calculate > the peak velocity in nm/s. Then you read the peak value > from your ADC and that allows you to compute the > velocity sensitivity of your seismograph in nm/s per bit. > By observing your backgraound noise level in bits during normal > damped operation you can convert it to nm/s. > > Or am I making a stupid mistake? > > And what is a good value for sensitivity and background noise level? > When I do the tests above, it looks like I have a sensitivity of > about 120nm/s/bit and my noise level is about +/- 3. I have > a 16 bit ADC so should I crank up the analog gain a tad? > > The reason I am trying to calibrate my Lehman is that I just > got it working and I can not figure why it detects some quakes > well and others poorly. I am comparing my results with those > posted on seismicnet. Especially the results from Herndon, VA > which is just a few miles away from me at Bailey's Xroads, VA. > I am trying to figure out whether I need more gain or is my location > on a office building basement slab next to a busy street just too noisy? > > TIA for any help, > > Dave Saum > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: seismograph calibration? From: Karl Cunningham karlc@....... Date: Tue, 14 Nov 2000 15:41:34 -0800 Hi Dave I expect your calibration idea will work, but a couple of thoughts come to mind. 1. I think this would only test the system at the natural period of the Lehman. The response of the coil / magnet arrangement may not be flat with frequency, and the electronics may not be either. 2. I assume your amplitude measurement is visual. If the magnitude of the response of the coil / magnet is not proportional to the amplitude of the swinging pendulum over the range of operating amplitudes, the gain may be different when the amplitude is large enough to see than when it is in the nanometer range due to earthquakes. I think this might be a possibility since, in some arrangements, the field gradient of the magnet may not be very uniform. Wishing to get the largest dynamic range I can, I run my gain so that the lowest background noise is about +/- 4 counts. And it's a rare day that it gets that low. Typical is +/- 20 counts, ranging to +/- 75 counts during storms. One thing that may make your record different from others is frequency response, both in your equipment and in your location (soil type). Another is the orientation of your seismometer (NS vs EW). Hope this helps. Karl Cunningham PSN Station #40 At 05:07 PM 11/14/2000 -0500, you wrote: >Suppose you just take the damping off a Lehman pendulum and >give it a little shove. It will begin to oscillate and if you >know the period and the amplitude then you can calculate >the peak velocity in nm/s. Then you read the peak value >from your ADC and that allows you to compute the >velocity sensitivity of your seismograph in nm/s per bit. >By observing your backgraound noise level in bits during normal >damped operation you can convert it to nm/s. > >Or am I making a stupid mistake? > >And what is a good value for sensitivity and background noise level? >When I do the tests above, it looks like I have a sensitivity of >about 120nm/s/bit and my noise level is about +/- 3. I have >a 16 bit ADC so should I crank up the analog gain a tad? > >The reason I am trying to calibrate my Lehman is that I just >got it working and I can not figure why it detects some quakes >well and others poorly. I am comparing my results with those >posted on seismicnet. Especially the results from Herndon, VA >which is just a few miles away from me at Bailey's Xroads, VA. >I am trying to figure out whether I need more gain or is my location >on a office building basement slab next to a busy street just too noisy? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: seismograph calibration? From: SW6079@....... Date: Tue, 14 Nov 2000 18:49:52 EST I too had wondered about my Lehman in the past... I missed two quakes I felt sure I should have detected. Both were about 100 miles from my location. I reviewed the locations on a large map, then it became obvious to me. The locations were almost exactly perpendicular to my boom!! Armed with this, the P wave at least was visible, and a careful review indeed showed my background noise was way up. Your situation may not be as simple, but I thought I'd mention it anyway. Good Luck, Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: calibration info From: sean@........... Date: Wed, 15 Nov 2000 01:28:05 -0600 (CST) Dave, Unless you have a very wide range digitizer (like 24 bits), any visible motion of the seismic mass should be grossly overloading your system when you are operating at a decent sensitivity. This could only be done properly if a carefully designed attenuator is installed between the seismometer and amplifier. We even need to use such an attenuator when using our hydraulic shake table with L4-C seismometers for telemetry stations. Even though the table range is 0.1 to 100 microns, we use a 40db (100:1) attenuator to keep the data from clipping in the amplifier. We cannot directly see the 100 micron (0.1 millimeter) motion at 1 hz, but we can feel it at 10 hz. (We use a 1000:1 optical lever indicator and an LVDT to monitor the table displacement.) Determining the calibration of the sensor coil only requires a simple multimeter, which is essential for almost any seismometer work, and a calibrated weight set. You can buy a 1 gram to 500 gram set from McMaster for $52, or just 5 weights, 1 gram thru 20 grams, (all you should need for a seismometer) for $15. This will allow the sensitivity of the coil and magnet to be determined by several methods, most commonly by applying a force with a weight and then restoring the resulting offset with a current. The resulting sensitivity of Newtons/Ampere is the same as the velocity output of Volts/meter/second. For example, if 1 gram is balanced (by using a potentiometer and battery thru the meter) by 1 milliampere, the sensitivity is (0.001 kgram / 0.001 Ampere)*9.8 m/sec^2 = 9.8 N/A or 9.8 V/m/s. The potentiometer can be a 10k ohm volume control from Radio Shack, used with an AA battery and clip leads. The normal background noise for a seismometer like a Lehman are the 6-second microseisms, usually caused by storms off the east coast. Away from the immediate shore (100km) these run 2 to 4 microns peak- to-peak, but can be ten times that during a hurricane or a Nor'easter. For a seismometer sensitivity of 100 V/m/s, an amplifier with a gain of 100 is needed to raise the signal from the microseisms to about 20 millivolts. This would provide about 100:1 signal to noise if the least count of a 10 volt, 16-bit digitizer is about 0.30 millivolts. Also note that how well you record a quake depends on your relationship to the source mechanism. Earthquakes are rarely point sources of energy that propagate evenly in all directions. They are called "double couple" sources because the energy radiates predominately in two directions. For the common right-lateral fault, like the San Andreas or New Madrid systems, the fault on the east side moves north, and the west moves south. Thus there is much less energy radiated east and west. The converse is the situation for a north-south thrust fault: the east moves up, or the west moves down, radiating less energy North and south. This is why magnitude determinations can vary by half a unit from an array of stations. And why sometimes we record much less than we expect. The usual way to study the local background noise and the relative sensitivity of a station and site is to compare the power spectral density to the USGS noise models. This is a bit more complex, but I could review it if necessary. There are some examples on my web site. If you need me to repeat the rest of the calibration info, let me know. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VHF telemetry From: barry lotz gbl@....... Date: Wed, 15 Nov 2000 16:40:31 -0800 Sean Thomas With the higher availibility of cell phones, I was toying with the idea of leaving a cell phone with a remote sensor and downloading the data every few nights during cheaper rates. It probable would only work for a single sight though. It seems less complicated but there probably isn't reasonably priced available cell access in very remote locations. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New event From: barry lotz gbl@....... Date: Wed, 15 Nov 2000 17:39:32 -0800 Greetings Red Puma says 6.4 @ New Britain Region PNG.( 04:56:21) Seems more like 7.4 ??? Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: "David A. Nelson" davenn@........... Date: Thu, 16 Nov 2000 17:53:15 +1100 At 17:39 15/11/00 -0800, you wrote: >Greetings > Red Puma says 6.4 @ New Britain Region PNG.( 04:56:21) Seems more >like 7.4 ??? > Regards >Barry welllll..... red puma is always at least a magnitude low its a given :) NEIC... 00/11/16 04:54:56 3.97S 152.32E 33.0 8.0Ms B NEW IRELAND REGION, P.N.G. 1st event to hit Mag 8 for a long time i think the last one was the 8.1 balleny island off the antartica coast a couple of yrs back cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 13 Monash Rd., Gladesville, (Sydney) 2111 NSW, Australia http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: New event From: "francesco" franuc@...... Date: Thu, 16 Nov 2000 08:40:23 +0100 USGS: 00/11/16 04:54:56 3.97S 152.32E 33.0 8.0Ms NEW IRELAND REGION, P.N.G. here in Italy , good traces, but I think that these magnitudo it's too greate..... I will post my files Francesco Italy. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: barry lotz gbl@....... Date: Wed, 15 Nov 2000 22:33:52 -0800 Dave Truely amazing. I'm still getting surface waves after 5-6 hours. It's the first time I've seem distant surface waves on a short period vertical accelerometer I have. Regards Barry "David A. Nelson" wrote: > > welllll..... red puma is always at least a magnitude low its a given :) > > NEIC... > 00/11/16 04:54:56 3.97S 152.32E 33.0 8.0Ms B NEW IRELAND REGION, P.N.G. > > 1st event to hit Mag 8 for a long time i think the last one was the 8.1 > balleny island off the antartica coast a couple of yrs back > > cheers > Dave > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 13 Monash Rd., > Gladesville, (Sydney) > 2111 > NSW, Australia > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Rabaul quakes From: BOB BARNS roybar@........ Date: Thu, 16 Nov 2000 12:11:36 -0500 Hi, Spectacular! Even the 7.7 exceeded (slightly) the 16 bit A/D capacity here in New Jersey. Motion was above background until about 5 hrs. after the 7.7 arrived. A "Geotech Blastcorder Mod. 5050" is on ebay #499098344, ends 11/21. It looks like it may be a short period seismograph. Can someone on this net tells us what this thing does? Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Geotech Blastcorder Mod. 5050" is on ebay #499098344 From: Doug Crice dcrice@............ Date: Thu, 16 Nov 2000 09:33:41 -0800 Geotech Blastcorder I don't recognize this specific instrument, but most likely it's designed to record vibrations from dynamite blasts. There is a standard that says a particle velocity of 2-inches/second is the threshold for creating damage to structures. Whenever people use explosives for one reason or another, such occasions are followed by damage claims from the neighbors, even for cracks full of dirt and cobwebs that have obviously been there for years. To try and introduce some logic into the legal process, the blasters will set out instruments to record the actual vibrations around the area of the explosions (also works for pile driving or even big trucks). The vibration records are used in the lawsuits. The instrument consists of a 3-axis set of geophones (seismometers to you earthquake fans), some amplification, an automatic triggering device, and a means to record the maximum velocity (such as a strip chart recorder). Judging by the knobs, this one looks like an antique. Modern versions of this instrument are fully solid state (using digital memory to store the information) stand-alone devices that connect to a PC for much more complete analysis of the data. Normally, the systems contain a vertical and two horizontal 4.5-Hz geophones, which one of the PSN group might like to salvage as a sensor for local events. The strip chart might be usable if working and if you can still get paper for it, as would the fiberglass carrying case. In other words, buy it for the parts but don't pay too much. Doug Crice __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: EMON time From: "Randall Pratt" randallpratts@.......... Date: Thu, 16 Nov 2000 18:07:32 -0600 Greetings to All, I have developed a problem within EMON relating to the time stamps. If the file spans a date change the time will not register after midnight. In the case of display using QuakeVue the file will display but the zoom will be blank if the beginning selection marker is placed after midnight. When the file is displayed in WinQuake the phases will not display when the P and S markers are set. Also, the minutes and seconds will display for the cursor position but the hour remains at zero. Finally and very confusing, the file start time displayed on the EMON screen is about 50 minutes later than the actual file start time and the time displayed in QuakeVue or the DOS directory. The current time at the top of the screen is correct. If I use PSN2Text program to read the file, the end time is recorded correctly. I'm running on an old 286 system. Could this be related to the Y2K and BIOS? Randy Pratt 1200 E 2nd Ave Mitchell, SD 57301 (605) 996-0907 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: EMON time From: "Ted Blank/Portsmouth/IBM" ted@.......... Date: Thu, 16 Nov 2000 20:46:07 -0500 Randy, Can you send me one of the mis-behaving files, to ted@........... And please let me know what version of EMON (and QUAKEVU) you are using. Regards, Ted Blank "Randall Pratt" @.............. on 11/16/2000 07:07:32 PM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: "PSN List" cc: Subject: EMON time Greetings to All, I have developed a problem within EMON relating to the time stamps. If the file spans a date change the time will not register after midnight. In the case of display using QuakeVue the file will display but the zoom will be blank if the beginning selection marker is placed after midnight. When the file is displayed in WinQuake the phases will not display when the P and S markers are set. Also, the minutes and seconds will display for the cursor position but the hour remains at zero. Finally and very confusing, the file start time displayed on the EMON screen is about 50 minutes later than the actual file start time and the time displayed in QuakeVue or the DOS directory. The current time at the top of the screen is correct. If I use PSN2Text program to read the file, the end time is recorded correctly. I'm running on an old 286 system. Could this be related to the Y2K and BIOS? Randy Pratt 1200 E 2nd Ave Mitchell, SD 57301 (605) 996-0907 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Ferrite mat'l From: barry lotz gbl@....... Date: Sat, 18 Nov 2000 05:13:21 -0800 Hi All I was wondering , Sean Thomas has described in detail how to construct a speaker style coil for use in a smt8 sensor. Various factors were discussed to improve the strength of the coil/magnet . My question, to Sean Thomas and all, is would the use of ferrite over steel improve the magnet field concentration and therefore sensor performance. I have seen various ferrite shapes. I'm not sure how well it machines. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Ferrite mat'l From: "George Harris" gjharris@............. Date: Sun, 19 Nov 2000 09:17:33 -0800 Barry, There are difficulties which make ferrite unsuitable. The primary one is that the maximum flux denisty is much less than iron. The second is that ferrites can only be ground to shape. Thay are so brittle and hard that any other method of forming is nearly impossible. ----- Original Message ----- From: barry lotz > Hi All > I was wondering , Sean Thomas has described in detail how to > construct a speaker style coil for use in a smt8 sensor. Various > factors were discussed to improve the strength of the coil/magnet . My > question, to Sean Thomas and all, is would the use of ferrite over > steel improve the magnet field concentration and therefore sensor > performance. I have seen various ferrite shapes. I'm not sure how well > it machines. > Regards > Barry > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: calibration info From: "David Saum" DSaum@............ Date: Sun, 19 Nov 2000 14:22:17 -0500 > From: sean@........... > Date: Wed, 15 Nov 2000 01:28:05 -0600 (CST) > The normal background noise for a seismometer like a Lehman are the > 6-second microseisms, usually caused by storms off the east coast. > Away from the immediate shore (100km) these run 2 to 4 microns peak- > to-peak, but can be ten times that during a hurricane or a Nor'easter. > For a seismometer sensitivity of 100 V/m/s, an amplifier with a gain > of 100 is needed to raise the signal from the microseisms to about 20 > millivolts. This would provide about 100:1 signal to noise if the least > count of a 10 volt, 16-bit digitizer is about 0.30 millivolts. Here is some noise and signal data from my first Lehman which I am still debugging. It looks like the noise is peaked near 6 seconds as you suggest. Does this look OK to you? http://www.infiltec.com/seismo/nois-amp.gif noise data http://www.infiltec.com/seismo/nois-fft.gif noise spectra http://www.infiltec.com/seismo/qake-amp.gif 7.5 quake data http://www.infiltec.com/seismo/qake-fft.gif 7.5 quake spectra I have increased the gain about 5x since I made the measurements estimating a sensitivity of 120 nm/s/bit and my absolute noise levels are up quite a bit, but it looks like I still have lots of adc dynamic range (unless the big one hits VA). My system sits on the basement slab of a VA office building about 100 feet from an continuously operating HVAC unit, with a major road about 100 ft on one side, and a McDonalds drive through about 50 ft away on the other. During the day the record shows many spikes similar to what happens when someone walks near the pendulum and deforms the slab. I get some pretty quiet data in the middle of the night when the Big Macs go home. My pendulum pivots on a ball bearing resting on a glass plate, and it seemed pretty easy adjust it for an 18 second period. My home brew electronics board only has 3 chips: one low noise opamp, one switched capacitor 8 pole bessel filter chip, and one PIC microprocessor with built-in 16 bit adc and serial output ports. I run a serial cable to my PC directly from the mpu, and system power (~3ma) is drawn from the serial port. I log the serial data at 16 sps with the Amaseis freeware which can produce files for input to WinQuake. My data logging computer is an old P90 that simultaneously runs SETI@HOME and is used for other odd jobs, so Amaseis does not seem to be using much of its resources. Caio, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Ferrite mat'l From: ChrisAtUpw@....... Date: Sun, 19 Nov 2000 17:51:20 EST In a message dated 18/11/2000, gbl@....... writes: > would the use of ferrite over > steel improve the magnet field concentration and therefore sensor > performance. I have seen various ferrite shapes. I'm not sure how well > it machines Hi there Barry, The flux density of ferrites is lower than Alnico or Ticonal so you need mre of it, the temperature coefficient is much higher and it can only be machined by wet grinding. If you don't demagnetise it first, all the ground material sticks to the magnet. Then you have to magnetise it again. It is often used as large chunky disks in cheaper loudspeakers, but they may be glued in place, which makes the soft iron pole pieces difficult to machine (if you need to increase the gap). With the normal speaker constructions, you get a lot of stray magnetic field. You may wish to use it for cost reasons, but other permanent magnet materials are likely to give you 'better' performance with smaller magnets. I would not choose to use magnetised high carbon steel either. Mild steel is OK for pole pieces. It is better if it is either electroplated or painted to prevent corrosion. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: calibration info From: ChrisAtUpw@....... Date: Sun, 19 Nov 2000 18:32:01 EST In a message dated 19/11/2000, DSaum@............ writes: > Here is some noise and signal data from my first Lehman which I > am still debugging. It looks like the noise is peaked near 6 seconds as > you suggest. Does this look OK to you? Hi there Dave, Just a few thoughts. What does the output fft look like if you a) substitute an equivalent resistor for the coil and b) then reduce the gain of the input amplifier to unity? The noise below 0.05 Hz looks a bit high and I was wondering if it was due to the low pass filter, or to ambient noise? Filters made using OpAmps may have a lower inherent noise. > During the day the record shows many spikes > similar to what happens when someone walks near the pendulum and > deforms the slab. I get some pretty quiet data in the middle of the night > when the Big Macs go home Could be magnetic or mechanical or both. Did your fft represent the quietest period or was it average over the day? Hope the comment is helpful, Chris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: iron and ferrite From: sean@........... Date: Mon, 20 Nov 2000 14:45:56 -0600 (CST) Barry, Regarding the use of ferrite or soft iron for magnet structures. There is considerable information on ferrites and transformer laminate alloys in the "Reference Data for Radio Engineers". A first point is that steel as in carbon steel is not used for magnetics: various "soft iron" alloys are used. The most common are the silicon (4% Si/Fe) alloys with permeabilities to 30,000. Then there are the Cobalt and Nickel alloys with higher flux densities, and then there are the Permalloy series, which includes Mumetal, with permeabilities from 100,000 to over 600,000. These are also expensive, since they can be up to 80% nickel. The tradeoff the other way are that the nickel alloys saturate at much lower levels (10 to 16k gauss) than the soft silicon types (20k gauss), with the Cobalt alloys having the highest saturation at 24k gauss. Ferrites are a ceramic made with iron oxide (Fe,2/O,4) and trace elements. Their permeabilities run 3000 to 5000. They are used primarily for high frequency transformers and inductors where eddy current losses in iron materials would be excessive. Like for the flyback transformer in a TV set, the 16 khz drive would require laminates 0.0001" thick, so a cast ferrite core is used. They are used for switching power supplies because the switching frequency is very high, and for radio frequency work where high inductances are not needed but low loss is essential. Regarding my description of the magnet assembly for the feedback transducer: I was shopping for hardware I could buy that would create a coil/magnet with an adequate generator constant, hence the assembly of "bought" parts that have not been modified other than filing edges. Its main advantage is that it is repeatable. I am sure that a commercial iron assembly could do much better with the same rare-earth magnet, but I have not explored the options. As for the application, there is little to be gained by increasing the feedback transducer constant other than extending the high frequency response, which is about 30 hz in the present design. A more compact transducer would help in a more portable design, and higher flux density would allow for a larger annular gap so as to provide better coil clearance over a shorter arc range of motion. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: iron and ferrite From: barry lotz gbl@....... Date: Mon, 20 Nov 2000 13:37:00 -0800 Chris & Sean Thomas Thanks guys for the help. Sean Thomas- that's what I wanted to here. I was only interested in increasing the transformer constant but if the current design will be ok for <30 hz then I'm happy. I will check out the reference.The Radio Shack speaker coil that I've incorporated in a built smt8 style sensor works well. I guess one could use two if one wanted to pull his hair out with twice the clearance concerns. :} Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Kinemetrics and Lehman From: "Kareem Lanier" kareemjupiter@............. Date: Tue, 21 Nov 2000 07:02:39 -0800 Does anyone know the best way to connect a home built Lehman sensor to a Kinemetrics PS2 System? I'm located in an apartment near a busy road and I'm having a hard time recording quakes over the local, high frequency noise. I'm hoping to record low frequency events, quakes and hopefully I can get rid of the local noise in doing so. Kareem Lanier Discover and Explore! www.kareemjupiter.com Subject: Re: calibration info From: "David Saum" DSaum@............ Date: Tue, 21 Nov 2000 12:02:23 -0500 > Subject: Re: calibration info > From: ChrisAtUpw@....... > Date: Sun, 19 Nov 2000 18:32:01 EST > > In a message dated 19/11/2000, DSaum@............ writes: > > > Here is some noise and signal data from my first Lehman which I > > am still debugging. It looks like the noise is peaked near 6 seconds as > > you suggest. Does this look OK to you? > > Hi there Dave, > > Just a few thoughts. What does the output fft look like if you a) > substitute an equivalent resistor for the coil and b) then reduce the gain of > the input amplifier to unity? The noise below 0.05 Hz looks a bit high and I > was wondering if it was due to the low pass filter, or to ambient noise? > Filters made using OpAmps may have a lower inherent noise. I tried to do what you suggested and all I see is what looks to me to be 3db/oct noise slope in both cases: http://www.infiltec.com/seismo/nois10ka.gif noise with 10k in place of coil - amp http://www.infiltec.com/seismo/nois10kf.gif noise with 10k in place of coil - fft http://www.infiltec.com/seismo/nois1xa.gif noise at unity gain, no coil - amp http://www.infiltec.com/seismo/nois1xf.gif noise at unity gain, no coil - fft So I guess my filter chip is not doing anything and all I have is the RC filter that I was using to get rid of the switching noise. Hmmm. Does this mean I have to give back my diploma to the Radio Shack school of electronics? I find it interesting that a Lehman works pretty well with only a single pole RC lowpass filter! http://www.infiltec.com/seismo/001117x.gif I guess my fallback for keeping my system simple is to replace my switched cap filter chip with an opamp chip configured as a 2 or 4 pole bessel filter. I am not sure yet why my MAX7401 8 pole bessel filter chip is not doing anything. It could be a stupid wiring problem on my board. But on re-reading the spec sheet it says "Maximum Capacitive load at OUT is min 50 pfd, typical 500 pfd". That could be my problem since my RC filter cap the output is in the ufds. I thought I set the Maxim corner frequency to 4 Hz, so the sampling frequency would be 100x=400 Hz. I guess that when the spec sheet recommends RC filtering for the sampling noise, it assumes that you have much higher corner frequencies so you can limit your RC capacitor size to pfds? If this Maxim output capacitance is the problem then only solution I can see is to put a unity gain amp between the filter chip and the RC. Ideas? > > During the day the record shows many spikes > > similar to what happens when someone walks near the pendulum and > > deforms the slab. I get some pretty quiet data in the middle of the night > > when the Big Macs go home > > Could be magnetic or mechanical or both. Did your fft represent the > quietest period or was it average over the day? My system noise record was from 9 UT or 4 AM local time. Pretty quiet. During the day it would be similar but riding on spikes every few minutes. These spikes seem to be related to slab tilting, since they look like what happens when I walk over to the pendulum. Here is an hour of system noise at noon local time. The big spikes may be me walking past the pendulum to get a Big Mac. http://www.infiltec.com/seismo/nois-amp.gif noise at 4am local - amp http://www.infiltec.com/seismo/nois-fft.gif noise at 4am local- fft http://www.infiltec.com/seismo/nois12na.gif noise at noon local - amp http://www.infiltec.com/seismo/nois12nf.gif noise at noon local - fft Ciao, Dave __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: calibration info From: Karl Cunningham karlc@....... Date: Tue, 21 Nov 2000 10:29:46 -0800 Hi Dave -- Do you have a schematic of your analog section that you could put up as a gif? I assume your gain stage is before the filter chip. It may be that with the gain at unity, your predominant noise source is the Maxim filter chip and that's why you see the single-pole roll off of noise. These chips have a certain amount of noise that they generate themselves and if your signal is below this, it will be lost in the noise of the filter chip. But this doesn't mean that the filter chip isn't doing any good -- when a larger signal comes along, it should do its job. It looks to me that with the gain at unity, the amount of noise you are seeing is getting down pretty low in terms of A/D counts. Some of it may be A/D converter noise. What does the noise look like if you remove the Maxim chip and short the input of your RC filter to ground? The maximum output capacitance spec for the Maxim filter is probably there to avoid oscillation of their output stage. Many analog IC's with low-power (spelled wimpy) output stages aren't stable driving capacitive loads. But the series resistor at the input of your RC filter should keep the Maxim filter chip from seeing the full capacitive load and get around the problem. If the value of that resistor is 10K or above, you shouldn't have any problem. And it may work with values down to 1K. If you put a scope on the output of the filter chip, look to see if there is any significant signal (oscillation) in the range of 1MHz. A little bit of signal is usually there due to pickup from AM radio stations and other transmitters in the area. If it's not more than 50mV or so, then you're probably ok for oscillations. Hope this helps. Karl Cunningham At 12:02 PM 11/21/2000 -0500, you wrote: >I tried to do what you suggested and all I see is what looks to me to >be 3db/oct noise slope in both cases: > >http://www.infiltec.com/seismo/nois10ka.gif noise with 10k in place of >coil - amp >http://www.infiltec.com/seismo/nois10kf.gif noise with 10k in place of >coil - fft >http://www.infiltec.com/seismo/nois1xa.gif noise at unity gain, no >coil - amp >http://www.infiltec.com/seismo/nois1xf.gif noise at unity gain, no >coil - fft > >So I guess my filter chip is not >doing anything and all I have is the RC filter that I was >using to get rid of the switching noise. Hmmm. Does >this mean I have to give back my diploma to the Radio >Shack school of electronics? > >I find it interesting that a Lehman works pretty well >with only a single pole RC lowpass filter! >http://www.infiltec.com/seismo/001117x.gif >I guess my fallback for keeping my system simple is to >replace my switched cap filter chip with an opamp chip >configured as a 2 or 4 pole bessel filter. > >I am not sure yet why my MAX7401 8 pole bessel >filter chip is not doing anything. It could be a stupid >wiring problem on my board. But on re-reading the >spec sheet it says "Maximum Capacitive load at OUT is >min 50 pfd, typical 500 pfd". That could be my problem since my >RC filter cap the output is in the ufds. I thought I set the Maxim >corner frequency to 4 Hz, so the sampling frequency would >be 100x=400 Hz. I guess that when the spec sheet recommends RC >filtering for the sampling noise, it assumes that you have >much higher corner frequencies so you can limit your RC >capacitor size to pfds? If this Maxim output capacitance is the problem >then only solution I can see is to put a unity gain amp >between the filter chip and the RC. Ideas? > >> > During the day the record shows many spikes >> > similar to what happens when someone walks near the pendulum and >> > deforms the slab. I get some pretty quiet data in the middle of the >night >> > when the Big Macs go home >> >> Could be magnetic or mechanical or both. Did your fft represent the >> quietest period or was it average over the day? > >My system noise record was from 9 UT or 4 AM local time. Pretty quiet. >During the day it would be similar but riding on spikes every few >minutes. These spikes seem to be related to slab tilting, since >they look like what happens when I walk over to the pendulum. >Here is an hour of system noise at noon local time. The big spikes >may be me walking past the pendulum to get a Big Mac. > >http://www.infiltec.com/seismo/nois-amp.gif noise at 4am local - amp >http://www.infiltec.com/seismo/nois-fft.gif noise at 4am local- fft >http://www.infiltec.com/seismo/nois12na.gif noise at noon local - amp >http://www.infiltec.com/seismo/nois12nf.gif noise at noon local - fft __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: latest Lehman Sensor info needed From: "Kareem Lanier" kareemjupiter@............. Date: Tue, 21 Nov 2000 18:36:30 -0800 I need the illustrations and a list of the hardware needed to build a Lehman Sensor. Does anyone have the latest info on this. Kareem Lanier Discover and Explore! www.kareemjupiter.com Subject: Re: latest Lehman Sensor info needed From: "Ted Blank" ted@.......... Date: Tue, 21 Nov 2000 22:08:43 -0500 Kareem, If you can get to a library with Scientific American on microfiche, ask for the July 1979 issue and read the original plans right there in the Amateur Scientist column. You can print them out on most microfiche machines. I think there are better amp/filter designs around, but that one worked for a lot of people. (The schematic is wrong though - the correction is in the August issue). Regards, Ted Blank IBM Global Services - Performance Management and Capacity Planning at the Washington Systems Center Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 Outside: (603) 433-9201 Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... "Kareem Lanier" @.............. on 11/21/2000 09:36:30 PM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: "PSN News" cc: Subject: latest Lehman Sensor info needed I need the illustrations and a list of the hardware needed to build a Lehman Sensor. Does anyone have the latest info on this. Kareem Lanier Discover and Explore! www.kareemjupiter.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: latest Lehman Sensor info needed From: "Larry Cochrane" cochrane@.............. Date: Tue, 21 Nov 2000 19:15:56 -0800 I have the original article on my web site at http://www.seismicnet.com/lehman.html. Regards, Larry Cochrane Redwood City, PSN ----- Original Message ----- From: "Ted Blank" To: Sent: Tuesday, November 21, 2000 7:08 PM Subject: Re: latest Lehman Sensor info needed > > Kareem, > If you can get to a library with Scientific American on microfiche, ask for > the July 1979 issue and read the original plans right there in the Amateur > Scientist column. You can print them out on most microfiche machines. I > think there are better amp/filter designs around, but that one worked for a > lot of people. (The schematic is wrong though - the correction is in the > August issue). > > Regards, > Ted Blank > > IBM Global Services - Performance Management and Capacity Planning at the > Washington Systems Center > Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 > Outside: (603) 433-9201 > Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 > Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... > > > "Kareem Lanier" @.............. on 11/21/2000 > 09:36:30 PM > > Please respond to psn-l@.............. > > Sent by: psn-l-request@.............. > > > To: "PSN News" > cc: > Subject: latest Lehman Sensor info needed > > > > I need the illustrations and a list of the hardware needed to build a > Lehman > Sensor. Does anyone have the latest info on this. > > Kareem Lanier > Discover and Explore! > www.kareemjupiter.com > > > > > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Virus Warning From: Doug Crice dcrice@............ Date: Tue, 21 Nov 2000 21:28:18 -0800 If you get a message with a link with the extension .pif or .exe, don't open it, it contains a virus. You can read about it at http://www.symantec.com/avcenter/venc/data/w95.mtx.htm -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Virus Warning From: "Ted Blank" ted@.......... Date: Wed, 22 Nov 2000 08:05:11 -0500 It is good advice not to run any executable that comes from an unknown (and therefore untrusted) source. .VBS is another type of executable file (Visual Basic Script) and some nasty viruses have come packaged this way. But not all attachments that end in .exe contain viruses. We used to distribute our programs as .exe attachments BLW (Before Larry and the Web). Just be doubly careful with these files. I also urge people to beware of a simple trick: naming a file something like funnyjoke.txt.exe where your eye might catch the 'txt' part and you double click on it (thinking that Wordpad or some editor will get invoked). Of course, Windows only looks at the last extension which is 'exe' and poof you are in trouble. BTW, the URL in the note below should end in html, not htm. Regards, Ted Blank IBM Global Services - Performance Management and Capacity Planning at the Washington Systems Center Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 Outside: (603) 433-9201 Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... Doug Crice @.............. on 11/22/2000 12:28:18 AM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: undisclosed-recipients:; cc: Subject: Virus Warning If you get a message with a link with the extension .pif or .exe, don't open it, it contains a virus. You can read about it at http://www.symantec.com/avcenter/venc/data/w95.mtx.htm -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Virus Warning From: Doug Crice dcrice@............ Date: Wed, 22 Nov 2000 07:47:16 -0800 I know enough to look out for .vbs or .exe files, but this file ended in (random message).TXT.pif The message is one of many chosen at random by the virus. I didn't know that an executable file could have a .pif extension. Neither .exe or ..vbs was present. Clicking on that link to Symantec doesn't seem to work, but typing it in does. Go figure. Doug Ted Blank wrote: > > It is good advice not to run any executable that comes from an unknown (and > therefore untrusted) source. .VBS is another type of executable file > (Visual Basic Script) and some nasty viruses have come packaged this way. > But not all attachments that end in .exe contain viruses. We used to > distribute our programs as .exe attachments BLW (Before Larry and the Web). > Just be doubly careful with these files. > > I also urge people to beware of a simple trick: naming a file something > like funnyjoke.txt.exe where your eye might catch the 'txt' part and > you double click on it (thinking that Wordpad or some editor will get > invoked). Of course, Windows only looks at the last extension which is > 'exe' and poof you are in trouble. > > BTW, the URL in the note below should end in html, not htm. > > Regards, > Ted Blank > > IBM Global Services - Performance Management and Capacity Planning at the > Washington Systems Center > Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 > Outside: (603) 433-9201 > Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 > Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... > > Doug Crice @.............. on 11/22/2000 12:28:18 AM > > Please respond to psn-l@.............. > > Sent by: psn-l-request@.............. > > To: undisclosed-recipients:; > cc: > Subject: Virus Warning > > If you get a message with a link with the extension .pif or .exe, don't > open it, it contains a virus. > > You can read about it at > http://www.symantec.com/avcenter/venc/data/w95.mtx.htm > -- > Doug Crice http://www.georadar.com > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, California 95070 USA fax 408-867-4900 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Virus Warning From: "Ted Blank" ted@.......... Date: Wed, 22 Nov 2000 11:09:38 -0500 Sorry you got clobbered. The idiots who do this keep finding ways to hurt people for no reason. They probably capitalized the .TXT part to make it more likely we'd miss the .pif part. Regards, Ted Blank Doug Crice @.............. on 11/22/2000 10:47:16 AM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: psn-l@.............. cc: Subject: Re: Virus Warning I know enough to look out for .vbs or .exe files, but this file ended in (random message).TXT.pif The message is one of many chosen at random by the virus. I didn't know that an executable file could have a .pif extension. Neither .exe or ..vbs was present. Clicking on that link to Symantec doesn't seem to work, but typing it in does. Go figure. Doug Ted Blank wrote: > > It is good advice not to run any executable that comes from an unknown (and > therefore untrusted) source. .VBS is another type of executable file > (Visual Basic Script) and some nasty viruses have come packaged this way. > But not all attachments that end in .exe contain viruses. We used to > distribute our programs as .exe attachments BLW (Before Larry and the Web). > Just be doubly careful with these files. > > I also urge people to beware of a simple trick: naming a file something > like funnyjoke.txt.exe where your eye might catch the 'txt' part and > you double click on it (thinking that Wordpad or some editor will get > invoked). Of course, Windows only looks at the last extension which is > 'exe' and poof you are in trouble. > > BTW, the URL in the note below should end in html, not htm. > > Regards, > Ted Blank > > IBM Global Services - Performance Management and Capacity Planning at the > Washington Systems Center > Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 > Outside: (603) 433-9201 > Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 > Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... > > Doug Crice @.............. on 11/22/2000 12:28:18 AM > > Please respond to psn-l@.............. > > Sent by: psn-l-request@.............. > > To: undisclosed-recipients:; > cc: > Subject: Virus Warning > > If you get a message with a link with the extension .pif or .exe, don't > open it, it contains a virus. > > You can read about it at > http://www.symantec.com/avcenter/venc/data/w95.mtx.htm > -- > Doug Crice http://www.georadar.com > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, California 95070 USA fax 408-867-4900 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Virus Warning From: Mark Robinson other@............... Date: Thu, 23 Nov 2000 05:13:08 +1300 A pif file is a Program Information file ... a legacy from windows 3.1 .... it is excutable under windows. The trick with the two extensions relies on windows habit of hiding the extensions of known file types unless you change this option after the install. This leaves the file looking like a text file or a picture, which is then executed whjen the user double clicks on it. It is good practice to set windows to show the extensions of known filetypes. Mark Doug Crice wrote: > > I know enough to look out for .vbs or .exe files, but this file ended in > (random message).TXT.pif > > The message is one of many chosen at random by the virus. I didn't know > that an executable file could have a .pif extension. Neither .exe or > .vbs was present. > > Clicking on that link to Symantec doesn't seem to work, but typing it in > does. Go figure. > > Doug > > Ted Blank wrote: > > > > It is good advice not to run any executable that comes from an unknown (and > > therefore untrusted) source. .VBS is another type of executable file > > (Visual Basic Script) and some nasty viruses have come packaged this way. > > But not all attachments that end in .exe contain viruses. We used to > > distribute our programs as .exe attachments BLW (Before Larry and the Web). > > Just be doubly careful with these files. > > > > I also urge people to beware of a simple trick: naming a file something > > like funnyjoke.txt.exe where your eye might catch the 'txt' part and > > you double click on it (thinking that Wordpad or some editor will get > > invoked). Of course, Windows only looks at the last extension which is > > 'exe' and poof you are in trouble. > > > > BTW, the URL in the note below should end in html, not htm. > > > > Regards, > > Ted Blank > > > > IBM Global Services - Performance Management and Capacity Planning at the > > Washington Systems Center > > Office: 238 Highland St., Portsmouth, NH 03801 Tieline: 8-253-9969 > > Outside: (603) 433-9201 > > Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 > > Notes: Ted Blank/Portsmouth/IBM@IBMUS Internet: ted@.......... > > > > Doug Crice @.............. on 11/22/2000 12:28:18 AM > > > > Please respond to psn-l@.............. > > > > Sent by: psn-l-request@.............. > > > > To: undisclosed-recipients:; > > cc: > > Subject: Virus Warning > > > > If you get a message with a link with the extension .pif or .exe, don't > > open it, it contains a virus. > > > > You can read about it at > > http://www.symantec.com/avcenter/venc/data/w95.mtx.htm > > -- > > Doug Crice http://www.georadar.com > > 19623 Via Escuela Drive phone 408-867-3792 > > Saratoga, California 95070 USA fax 408-867-4900 > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > > > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > > -- > Doug Crice http://www.georadar.com > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, California 95070 USA fax 408-867-4900 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: test From: "Kareem Lanier" kareemjupiter@............. Date: Wed, 22 Nov 2000 13:52:02 -0800 test Subject: RE: Virus Warning From: Brian Glover belenus@........ Date: Wed, 22 Nov 2000 16:55:09 -0500 Is there a new virus we should be looking for, if so, what is its name=3F Belenus Subject: Re: Virus Warning From: Doug Crice dcrice@............ Date: Wed, 22 Nov 2000 14:17:49 -0800 Its name is w95.mtx, but it shows up on your computer as an attachment with a short phrase with the extension .pif and can be found in the Symantec data base at http://www.symantec.com/avcenter/venc/data/w95.mtx.html It was first seem in August and is apparently common in Asia. The tricky part is the extension doesn't end with .exe or .vbs as do most viri. Brian Glover wrote: > > Is there a new virus we should be looking > for, if so, what is its name? > Belenus -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: tectonic map site From: BOB BARNS roybar@........ Date: Thu, 23 Nov 2000 11:15:15 -0500 Hi gang, From Science Magazine, 17 Nov. 2000 http://www.aquarius.geomar.de/omc/omc_intro.html "Want to see fault lines around the Andes, fast? This site in Germany will make a map of any part of the world in various projection types...and stamp it with tectonic features..." Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 2 ebay items From: BOB BARNS roybar@........ Date: Thu, 23 Nov 2000 13:47:59 -0500 Hi gang, ebay # 504546666 is "Terra Technology Seismograph Model DCS-302 Data Logger" ends 11/29 ebay # 506893800 is "Infrasonic Microbarograph Sensors". ends 12/2 Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Winquake Reports From: Dick Webb dwebb2@.............. Date: Fri, 24 Nov 2000 12:19:01 -0500 Hi, I use Winquake and it's Event Report feature but have not been able to set it up to download either IRIS DMC or USGS qed data. I looked at the help files but could not figure out how to apply them. Have any of you had any luck. My specific need is to access files older that those in the NEIC Near Real Time report (which works well for me). Dick __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WINQUAKE From: Hrbtz@....... Date: Fri, 24 Nov 2000 15:43:00 EST Can any one tell me if WinQuake is compatible with the AS-1 seismic recorder? Thanks. Can any one tell me if WinQuake is compatible with the AS-1 seismic recorder?
 Thanks.
Subject: Telluric Currents... From: "Steve Olney" ollaneg@........... Date: Sun, 26 Nov 2000 12:33:26 +1100 G'day All, This may be off-topic for some, but I know there are many who are interested in experimentation for its own sake. I have done some experiments using the earth base antenna installation regarding measuring the potential difference variations over time. Go to my experimental web pages (see address below) and scroll down to Telluric Currents. I have some graphs of portions of about 30 hours of data. Of particular interest is the presence of a 4.5 second period sinusoidal signal and a strange long-term period pulse train. To better appreciate the data I have converted and compressed the 30 hours of data into a WAV file so that you "hear" the data instead of viewing. Comments and explanations would be most welcome !!! 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.qsl.net/vk2zto http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation InfraSonic Experimentation Laser Comms DX Amateur Radio Astronomy ============================================= __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Caspian Sea + Magnetic Activity From: Arie Verveer ajbv@............ Date: Sun, 26 Nov 2000 13:54:59 +0800 This may be of interest, At http://www.iinet.net.au/~ajbv/ftp/Drum.html is a ( ULF ) magnetic recording for the 25/nov/200. It shows increased activity at 18:00 UTC. This might and I stress the work "might" be associated with the Ms 6.3 earthquake at the Caspian sea. The large pulses between 04:00 - 08:00 UTC are my car driving "near" the sensor. This Display is valid only for the next 19 hours when it will be updated. Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 4.6 Yellowstone files from M. Lamb From: meredith lamb mlamb1@.......... Date: Sun, 26 Nov 2000 13:03:54 -0800 Subject: Apology From: meredith lamb mlamb1@.......... Date: Sun, 26 Nov 2000 13:14:56 -0800 Sorry, I apologize for sending the event to the wrong list. Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Telluric Currents... From: "Steve Olney" ollaneg@........... Date: Mon, 27 Nov 2000 07:47:52 +1100 G'day All, Thanks for all the replies and comments (keep them coming). I will attempt to reply to them all this week. 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.qsl.net/vk2zto http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation InfraSonic Experimentation Laser Comms DX Amateur Radio Astronomy ============================================= __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: solar storm From: sean@........... Date: Sun, 26 Nov 2000 15:37:30 -0600 (CST) Regarding geomagnetic events and telluric currents: Rather than trying to associate them with earthquakes, a more probable cause is another large solar storm that erupted yesterday and is expected to cause radio and power grid disturbances today and tomorrow, with the Northern Lights taking in a southern range as far as N. California to Carolina. Maybe someone can report some more detailed info and sources, particularly the timing of the current swarm of storms. The AP reported 6 major flares in 48 hours. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WINQUAKE From: The Lahrs johnjan@........ Date: Sun, 26 Nov 2000 17:51:43 -0700 If you use Alan Jones' AmaSeis software with the AS-1, then you can save
an earthquake in PSN format and read it into WinQuake.
John

At 01:43 PM 11/24/00 , you wrote:
Can any one tell me if WinQuake is compatible with the AS-1 seismic recorder?
 Thanks.

* John C. and Jan H. Lahr                
*JohnJan@........                 &nb sp;   
* 1925 Foothills Road                    
* Golden, Colorado 80401-1718            
* (303) 215-9913                     ;     
* http://lahr.org/john-jan        & nbsp;      
Subject: Re: solar storm From: Arie Verveer ajbv@............ Date: Mon, 27 Nov 2000 09:17:44 +0800 Hi, I agree the association between all quakes and geomagnetic events is tenuous. Though in this case, one can read it a few ways. No association, or the geomagnetic activity triggered the quake or the activity was observed before the quake. On larry's system is two files that may be of interest. 000916a.au2 000916a.au4 The latter is the ULF radiation and the other is the recording of a local quake. What the data seems to show is a geomagnetic disturbance at the exact time of the quake. After a short travel time the quake was recorded. I also have a few more samples like this. This may be a coincidence or its real. If its real, then its worth looking into. Statistics will only tell. My guess is there is some triggering but statistical insignificant. There has been some examples of increased ULF radiation before a distant big (deep) quakes on quite geomagnetic days. Whatever the final conclusion, its just interesting monitoring these events. Cheers Arie > > Regarding geomagnetic events and telluric currents: > > Rather than trying to associate them with earthquakes, a > more probable cause is another large solar storm that erupted > yesterday and is expected to cause radio and power grid > disturbances today and tomorrow, with the Northern Lights > taking in a southern range as far as N. California to Carolina. > > Maybe someone can report some more detailed info and sources, > particularly the timing of the current swarm of storms. The AP > reported 6 major flares in 48 hours. > > Regards, > Sean-Thomas > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: solar storm From: "Bryan & Regina Goss" bgoss@.................. Date: Sun, 26 Nov 2000 22:00:25 -0600 http://www.tsixroads.com/~spardue/seismograph/seismograph.htm working on my seismograph look at the picks does it look ok?? ----- Original Message ----- From: Arie Verveer To: Sent: Sunday, November 26, 2000 7:17 PM Subject: Re: solar storm > Hi, I agree the association between all quakes and geomagnetic > events is tenuous. Though in this case, one can read it a few > ways. No association, or the geomagnetic activity triggered > the quake or the activity was observed before the quake. On larry's > system is two files that may be of interest. 000916a.au2 000916a.au4 > > The latter is the ULF radiation and the other is the recording of a > local quake. What the data seems to show is a geomagnetic disturbance > at the exact time of the quake. After a short travel time the > quake was recorded. I also have a few more samples like this. > > This may be a coincidence or its real. If its real, then its worth > looking into. Statistics will only tell. My guess is there is some > triggering but statistical insignificant. There has been some examples > of increased ULF radiation before a distant big (deep) quakes on > quite geomagnetic days. > > Whatever the final conclusion, its just interesting monitoring > these events. > > Cheers > > Arie > > > > > > Regarding geomagnetic events and telluric currents: > > > > Rather than trying to associate them with earthquakes, a > > more probable cause is another large solar storm that erupted > > yesterday and is expected to cause radio and power grid > > disturbances today and tomorrow, with the Northern Lights > > taking in a southern range as far as N. California to Carolina. > > > > Maybe someone can report some more detailed info and sources, > > particularly the timing of the current swarm of storms. The AP > > reported 6 major flares in 48 hours. > > > > Regards, > > Sean-Thomas > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Love waves from Mw 8.0 From: sean@........... Date: Sun, 26 Nov 2000 23:07:05 -0600 (CST) An interesting observation in the data from the Mw 8.0 quake in P.N.G. near Rabaul on November 16: For those of you operating long period horizontal seismometers, with digital recording, so you can see the time series in a relatively compressed form (on a drum or helical record the waves from successive rotations are seriously scrambled, especially with the Mw 7.7 second event.) The event generated a very impressive set of Love waves that are seen in the data of a horizontal sensor whose sensitive axis is normal to a line drawn toward the source. This is an SH type surface wave whose group velocity equals its phase velocity so it does not disperse or spread out as it travels over the surface of the earth. That is, repeated occurrences of it are very similar, and are labeled G1, G2, G3, etc, for repeat appearances traveling in the same direction. For this large quake, the mechanism was such that a large Love wave was generated propagating out both directions. From my station, very little Raleigh wave is evident on the vertical record. The first Love wave arrival at CCM is at 0542 Z, 48 minutes after the origin time of 0454. This would be the direct wave from the event. It has a period of about 80 seconds and a P-P amplitude of 320 microns/second on the North-South record, and about 110 microns/sec on the EW record. (meaning that the displacement here at St. Louis was about 4 mm ). It has traveled about 12 500 km, which is consistent with a velocity of 4.36 km/second for the shear wave at the surface. The wave that went the "long way" around the earth arrived at 0639z, or 57 minutes after the direct wave, and 105 minutes after the quake. Its amplitude is about 150 microns/second. Then the second occurrence of the direct wave arrives at 0813z, having gone around the earth once in 151 minutes, implying that the circumference of the earth is 39 500 km: approximately, as are my time values. Then the second arrival of the "long way" wave arrives at 0909z, again 57 minutes after the second direct wave. A these are clearly distinct (and at the wrong time) to be associated with the Mw 7.7, which has a very weak Love wave. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Good Xmas gift suggestion for kids From: "Ted Blank" ted@.......... Date: Sat, 25 Nov 2000 06:45:47 -0500 If you have (or know people who have) kids maybe 8 and up, Sierra makes a game called The Incredible Machine 3.0. My kids have enjoyed it for years - ok, I admit it, so do I. Basically you try to solve puzzles by arranging various contraptions rather like a Rube Goldberg. The "incredible" part to me is the animation - when you click Go the thing comes to life, gravity makes things fall, bouncing things bounce, mice turn cages to supply power to objects that need to rotate, candles (if you can light them with a flashlight and mag. glass) burn through ropes... I don't know why this thing doesn't get more press. Anyway, it's part of something called the Sierra Family Game Pak which I got for $15 on one of the web software sites. Your kids/nephews/nieces/grandkids will enjoy this one, and it's a welcome break from all the shoot-em-up junk. Regards, Ted Blank __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More Telluric "sounds"... From: "Steve Olney" ollaneg@........... Date: Mon, 27 Nov 2000 23:06:35 +1100 G'day All, Just added two more data runs in WAV and RealAudio format. Scroll down in the web page address given below to Telluric Currents and go to the sounds link. 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.qsl.net/vk2zto http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation InfraSonic Experimentation Laser Comms DX Amateur Radio Astronomy ============================================= __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Good Xmas gift suggestion for kids From: Mike Lozano mikel@............... Date: Mon, 27 Nov 2000 06:36:27 -0600 Hi Ted, If you'll give me the URL, I'll post it to my website - it gets 5000 hits a day from 19 countries. My educational website is aimed mostly at kids and their parents. Mike Lozano, mikel@............... http://www.sciencearea.com Ted Blank wrote: > If you have (or know people who have) kids maybe 8 and up, Sierra makes a > game called The Incredible Machine 3.0. My kids have enjoyed it for years > - ok, I admit it, so do I. Basically you try to solve puzzles by arranging > various contraptions rather like a Rube Goldberg. The "incredible" part to > me is the animation - when you click Go the thing comes to life, gravity > makes things fall, bouncing things bounce, mice turn cages to supply power > to objects that need to rotate, candles (if you can light them with a > flashlight and mag. glass) burn through ropes... I don't know why this > thing doesn't get more press. Anyway, it's part of something called the > Sierra Family Game Pak which I got for $15 on one of the web software > sites. Your kids/nephews/nieces/grandkids will enjoy this one, and it's a > welcome break from all the shoot-em-up junk. > > Regards, > Ted Blank > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Good Xmas gift suggestion for kids From: "Ted Blank" ted@.......... Date: Mon, 27 Nov 2000 09:48:38 -0500 Hi Mike, Just for the record I have no connection with these guys... Sierra Online is the maker. Their web site, http://www.sierra.com, shows only a game called "Return of Incredible Machine - Contraptions" for $29.95. I assume this is a new version but I haven't actually seen it work. The program I purchased, "The Incredible Machine 3.0" is apparently not being sold directly by Sierra but is available at many web sites as part of the "Family Fun Pack" for $15-$20. It also includes "3D-Ultra Pinball", "Print Artist Classic 3.0" and "Hoyle Classic Games" (cards plus Backgammon and CHeckers). A great bargain in my opinion since the Incredible Machine is worth the whole price alone. One site I found offering the Fun Pack is http://www.cdromaccess.com/html/pc/411puzz.htm for $17.95 and there are many more which can be found with a simple search for "Family Fun Pack" on the web. Feel free to include my "review" below on your site, but please note and correct my mistake - I called it "Family Game Pack", it is actually "Family Fun Pack". Hope lots of folks have lots of fun. Regards, Ted Blank Mike Lozano @.............. on 11/27/2000 07:36:27 AM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: psn-l@.............. cc: Subject: Re: Good Xmas gift suggestion for kids Hi Ted, If you'll give me the URL, I'll post it to my website - it gets 5000 hits a day from 19 countries. My educational website is aimed mostly at kids and their parents. Mike Lozano, mikel@............... http://www.sciencearea.com Ted Blank wrote: > If you have (or know people who have) kids maybe 8 and up, Sierra makes a > game called The Incredible Machine 3.0. My kids have enjoyed it for years > - ok, I admit it, so do I. Basically you try to solve puzzles by arranging > various contraptions rather like a Rube Goldberg. The "incredible" part to > me is the animation - when you click Go the thing comes to life, gravity > makes things fall, bouncing things bounce, mice turn cages to supply power > to objects that need to rotate, candles (if you can light them with a > flashlight and mag. glass) burn through ropes... I don't know why this > thing doesn't get more press. Anyway, it's part of something called the > Sierra Family Game Pak which I got for $15 on one of the web software > sites. Your kids/nephews/nieces/grandkids will enjoy this one, and it's a > welcome break from all the shoot-em-up junk. > > Regards, > Ted Blank > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Apology From: "Ted Blank" ted@.......... Date: Mon, 27 Nov 2000 10:03:15 -0500 Sorry everyone, meant to send that directly to Mike. But as long as you're reading this, hope you had a great Thanksgiving (all the Yanks anyway). Regards, Ted Blank __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fw: mb - Ms disciminant From: "Larry Cochrane" cochrane@.............. Date: Mon, 27 Nov 2000 17:52:29 -0800 Richard, Sorry, I can't help you. I'm sending this message to the Public Seismic Network mailing list. Maybe someone on the list can help. PSN'ers, if you can help please CC the list and send your message directly to Richard since he is not on the list. -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: "Richard J. Warburton" To: Sent: Friday, November 24, 2000 2:43 PM Subject: mb - Ms disciminant > Dear Larry, > I manufacture a very stable gravity meter (the 'Superconducting > Gravimeter'), which is very low noise up to about 1 mHz. Until > recently, I have not been much interested in higher frequencies, since > the range of frequencies from 1 mHz to 10 Hz seemed well covered by > other long period seismometers. Now, I believe that I might be able to > improve the 'SG' so that it could improve measurements in the 1 to 20 > mHz range. > > My knowledge of seismology is limited, but I know that the measurement > of mb-Ms is an important discriminant for separating underground > explosions from earthquakes. However, I have not yet found a simple and > clear explanation of how either mb or Ms is measured. What would be > most helpful would to find the exact definition of mb and Ms, and then > as an example show the incoming seismic wave train, the spectrum of the > wave train, and an illustration of the calculation of these two. > Advanced mathematics is okay as long as the result is "clarified" with > some examples. > > Is this available is any book or paper that you are aware of? > > Thanks much, > > Richard > > -- > Richard Warburton > GWR Instruments, Inc. > 6264 Ferris Square, Suite D > San Diego, California 92121 > phone: (858) 452-7655 > fax: (858) 452-6965 > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Telluric Currents responses... From: "Steve Olney" ollaneg@........... Date: Tue, 28 Nov 2000 22:38:38 +1100 G'day All, Thanks for all your responses. Instead of replying to each one individually I have summarised the responses on my web site. Go to the URL below and scroll down to Telluric Currents and take the Telluric "Sounds" link. From the "sounds" page scroll down to the bottom and take the "Comments" link. 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.qsl.net/vk2zto http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation InfraSonic Experimentation Laser Comms DX Amateur Radio Astronomy ============================================= __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN Fall Bay Area meeting From: Steve Hammond Shammon1@............. Date: Tue, 28 Nov 2000 16:06:05 -0800 To all PSN members that will be in the San Francisco Bay area during the AGU meeting: With the AGU meeting in San Francisco from December 15 to the 19th, the subject of having a PSN meeting has circulated in a number of off-line notes. Most of the AGU attendees will be flying in on Dec 14 and out on the 20th. Can anybody suggest where and when we might get together for a meeting? Regards, Steve Hammond __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Felt reporting From: The Lahrs johnjan@........ Date: Tue, 28 Nov 2000 19:56:05 -0700 If you feel an earthquake, be sure to report it on the USGS web site: http://neic.usgs.gov/neis/felt/report.html Your response will be included with others on maps showing the distribution of earthquake intensity. Kareem, I noticed that on your very interesting web site you also have a form for people feeling an earthquake. What do you do with the responses that you receive? It might be a good idea to point people to the USGS site mentioned above. Cheers, John At 08:02 AM 11/21/00 , you wrote: >Does anyone know the best way to connect a home built Lehman sensor to a >Kinemetrics PS2 System? > >Kareem Lanier >Discover and Explore! >www.kareemjupiter.com > > > John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: AGU or SSA get together From: sean@........... Date: Tue, 28 Nov 2000 20:58:32 -0600 (CST) An alternate consideration to having a PSN meeting concurrent with the AGU meeting is to wait and have it concurrently with the SSA (Seismological Society of America) meeting in mid April. This will also be in San Francisco, I believe at the Cathedral Hill hotel (where the AGU used to be held until it got too large). The meeting from April 18 thru 20 is on the 95th anniversary of the 1908 quake. Although is a smaller 3 day meeting, it actually attracts more seismologists than the massive (last year about 7000 papers about almost everything) AGU meeting. And springtime in San Francisco is much more enjoyable than the shortest days of December. But maybe there is enough interest to have a PSN gathering at both times. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismograph Timing From: "Robert L. Hancock" robert.hancock@........... Date: Tue, 28 Nov 2000 22:26:02 -0500 I have noticed periodic exchanges on the problems and solutions to obtaining the correct time for timing and keeping timed a seismograph.. I plan on building one in the forseeable future, and this along with other subjects has been of interest to me. Recently, I ran across a page from the US Naval Observatory, our official timekeeper, about computer programs that can be downloaded and used to maintain timing with computers I have installed one on my computer and was surprised at how much drift there was in my cpu clock. http://www.eecis.udel.edu/~ntp/software.html The main page for the US Naval Observatory is http://www.usno.navy.mil/ I am not certain how useful this will be to anyone, but thought I would mention it as I do remember having seen this source discussed. Most discussions seemed to be focused on either receiving WWV or a similar type signal, or using the timing obtained from the GPS satelites. This site has a large variety of programs utilizing many different operating systems. Some are shareware and free while others require registration and $. Hopefully this will help someone.......... Cheers, Bob Hancock Randolph, NJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismograph Timing From: Bob Smith bobsmith5@........ Date: Wed, 29 Nov 2000 07:31:42 -0500 Hello PSNers -- I "lurk" here as a result of a latent interest in seismology though I am not personally active in the field. I have, however, maintained a long standing professional and personal interest in the field of precision timekeeping. I can appreciate the importance of precision time references to seismology. The seemingly simple requirement of maintaining a precise time reference (clock) leads to a field that can become extremely complex when precision is taken to its limits. For your purposes I can suggest the following (in order of increasing precision): 1. Use your PC clock to time stamp or otherwise mark your plots. PC clocks are notorious for wandering all over the place however. In the absence of regular discipline they can be expected to accumulate errors in the order of 10s of seconds within a few days to a few weeks. There is sometimes discussion that improving the accuracy of the Xtal in the PC will improve the accuracy of the clock. This is doubtful, however, since much of the inaccuracy is traceable to failure of the OS to reliably service the timer interrupts. The accuracy of the PC's clock can probably be improved by regular (say daily) manual adjustments using the radio transmissions of WWV (as an example) as a reference. There are also I/O expansion cards available that carry a high accuracy time base which is often referenced to an oven stabilized (OCXO) or temperature compensated (TCXO) crystal oscillator. These can hook into the system BIOS so that calls for system time will be derived from the add-in reference. 2. The PC clock can also be disciplined in the manner suggested by Mr. Hancock using a program that communicates with the Network Time Protocol (NTP) or SNTP servers maintained by numerous sites throughout the world such as Tick and Tock at the USNO. A particularly nice package for this purpose is 4DTIME which is offered as a freeware package at http://www.thinkman.com This is true "freeware" not a "demo" or "evaluation" version. The only "payment" that Rob requests is an email describing your application and suggestions for improvement. If you are so lucky as to enjoy a full time internet connection such as I do through my cable modem, this software can be set to wake up periodically and do an automatic PC clock up date while running minimized. Using this technique you can probably maintain PC clock accuracy to better than 0.1 second. 3. Next would be using a WWV or WWVB radio time standard receiver. One of my favorites is the old (now obsolete) Heathkit GC-1000 Most Accurate Clock. This is a scanning HF receiver that samples the WWV transmissions on 5, 10, and 15 MHz and decodes the time signals which are used to discipline a local 6 MHz oscillator. I have the optional RS-232 output port installed on mine. This emits the local time base once per second. Using a reasonable antenna so that it gets regular updates, this clock will maintain time accuracy in the order of a few 10s of milliseconds. These things are becomming quite rare, so if you are lucky enough to run across one at a ham radio fest or yard sale, *grab* *it*!!. 4. Finally, through the efforts of Dr. Thomas A. Clark, W3IWI, a well known radio amateur and consummate tinkerer and a number of associates, truly precision GPS based time keeping has been brought to the level of amateurs. Dr. Clark has developed hardware/software solutions which bring the very high precision of the GPS satellite time bases to the common PC. Using his methods, sub-microsecond accuracy time bases become available to the amateur seismologist. Ultimately, time base accuracy in the order of a few 10s of nanoseconds is possible. For further information I suggest that you subscribe to the TAPR (Tuscon Amateur Packet Radio) TACGPS email list. Go to http://www.tapr.org and follow the links to the Special Interest Groups (SIG) mail lists subscription page. Also, visit http://www.synergy-gps.com/ Synergy specializes in marketing the Motorola family of Oncore GPS receiver modules which are great for timekeeping applications. In particular, the Oncore UT+ GPS receiver has been optimized for precision timekeeping purposes and is the one capable of serving up time to a precision of about 10 nanoseconds. 5. If that doesn't keep your seismometer happy, go buy an atomic standard. These occasionally show up on ebay! http://www.ebay.com Good luck and good time, Bob Smith "Robert L. Hancock" wrote: > > I have noticed periodic exchanges on the problems and solutions to > obtaining the correct time for timing and keeping timed a seismograph.. > I plan on building one in the forseeable future, and this along with > other subjects has been of interest to me. Recently, I ran across a > page from the US Naval Observatory, our official timekeeper, about > computer programs that can be downloaded and used to maintain timing > with computers I have installed one on my computer and was surprised at > how much drift there was in my cpu clock. > > http://www.eecis.udel.edu/~ntp/software.html > > The main page for the US Naval Observatory is > > http://www.usno.navy.mil/ > > I am not certain how useful this will be to anyone, but thought I would > mention it as I do remember having seen this source discussed. Most > discussions seemed to be focused on either receiving WWV or a similar > type signal, or using the timing obtained from the GPS satelites. This > site has a large variety of programs utilizing many different operating > systems. Some are shareware and free while others require registration > and $. > > Hopefully this will help someone.......... > > Cheers, > > Bob Hancock > Randolph, NJ > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: AGU or SSA get together From: John Taber taber@............. Date: Thu, 30 Nov 2000 05:11:49 +1300 (NZDT) Perhaps there can be a PSN meeting at the time of both AGU and SSA. That way people who will be in town for only one of the meetings can attend. I'll admit I have a personal bias for AGU since I'll be there and I greatly enjoyed the PSN meeting I attended 2 years ago. AGU includes a Saturday this year which might be an easier day for people to travel in from outside the area. Regards, John Taber __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: AGU or SSA get together From: John Hernlund hernlund@............ Date: Wed, 29 Nov 2000 14:08:35 -0800 John Taber wrote: > Perhaps there can be a PSN meeting at the time of both AGU and SSA. That > way people who will be in town for only one of the meetings can attend. > I'll admit I have a personal bias for AGU since I'll be there and I > greatly enjoyed the PSN meeting I attended 2 years ago. This sounds like fun. I would like to put faces to e-mails, but I will be restricted time and space-wise. I have a poster session on Sunday, and any place I go will have to be in walking distance of the Moscone Center... John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: AGU or SSA get together From: The Lahrs johnjan@........ Date: Wed, 29 Nov 2000 18:46:52 -0700 I would also vote for Saturday night, Dec. 16, as I also will not be going to the SSA. John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Quake in Iowa tonight? From: Mike Lozano mikel@............... Date: Thu, 30 Nov 2000 22:32:23 -0600 Hi everyone! Has anyone picked up any earthquake activity in or around Iowa this evening? A friend of mine who's a TV meteorologist just emailed me to report a swarm of calls reporting a tremor. Mike Lozano __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: HELP From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 30 Nov 2000 23:24:21 -0600 Ok I got my seismograph built and I used Larry's A/D card and = filter/amp, My question is how do I know if I have to much gain? It looked as if I did so I put 15k res at r29 this reduced noise but I = don't know if it was to much. I can walk across my shop floor 30x 40x concrete slab and going to seismograph I see the trace go up = about an inch then slowly go back to center when I walk away just the = opposite, The trace seems to drift up and down a little guess this is = normal?????? I really need help =20 this is before the damper and cover = http://www.tsixroads.com/~spardue/seismograph/seismograph.htm
Ok I got my seismograph built and I = used Larry's=20 A/D card and filter/amp, My question is how do I know if I have to much=20 gain?
It looked as if I did so I put 15k res = at r29 this=20 reduced noise but I don't know if it was to much. I can walk across my = shop=20 floor
30x 40x concrete slab and going to = seismograph I=20 see the trace go up about an inch then slowly go back to center when I = walk away=20 just the opposite, The trace seems to drift up and down a little = guess this=20 is normal??????
I really need help 
 
this is before the damper and cover ht= tp://www.tsixroads.com/~spardue/seismograph/seismograph.htm
 
Subject: RE: HELP From: steve hammond shammon1@............. Date: Thu, 30 Nov 2000 23:52:33 -0800 Bryan, You are at the fun part. I have two Lehman's and I use the older PSN amp design. I set my gain to 2000 and then adjust it up or down as needed. The operation you describe sounds correct for the stage you are at. I have a 12-bit A/D and can induce a count of -/+ 40-50 by walking next to the device. The amount of gain is governed by two factors. The gain of the amplifiers and the sensitivity of the device. I was looking at your pictures, nice work, so let me suggest the following, it should be doable when setting initial device sensitivity. Your boom looks like it is about 36-inches. With a 36-inch boom and .25 degrees of forward tilt of the base plate, a level boom will have a natural period of 18.2 seconds. If I were setting up the device, I would first set the gain to around 2000 and then set the undampened period of the device to 10-seconds making sure that the boom returns to center whenever after it is excited. Next, I would slowly lengthen the period to 20-seconds undampened and then adjust the damping magnets to stop the boom from swinging in 3 1/2 cycles. This will bring the dampened period to about 17-18 seconds. At that point you are ready to record and see what you get. Increase / decrease the amp gain based on urban noise thresholds. For the first 30 days or so the boom may drift off center overnight. This is due to the nature of the metal frame and the floor under it settling. At that point you are ready to wait and see... Another point, I can't emphasize how important an airtight cover is. I use a full sheet of 1/2-inch plywood to make a box 2X2X4 and then put 2" insulation foam board inside it which thermally protects the device from sudden temperature changes and tape the seams in the plywood and floor. Look'en good- Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: Bryan & Regina Goss [SMTP:bgoss@................... Sent: Thursday, November 30, 2000 9:24 PM To: psn-l@.............. Cc: Larry Cochrane Subject: HELP << File: ATT00001.html >> Ok I got my seismograph built and I used Larry's A/D card and filter/amp, My question is how do I know if I have to much gain? It looked as if I did so I put 15k res at r29 this reduced noise but I don't know if it was to much. I can walk across my shop floor 30x 40x concrete slab and going to seismograph I see the trace go up about an inch then slowly go back to center when I walk away just the opposite, The trace seems to drift up and down a little guess this is normal?????? I really need help this is before the damper and cover http://www.tsixroads.com/~spardue/seismograph/seismograph.htm __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake in Iowa tonight? From: Jim Hannon jmhannon@........ Date: Fri, 01 Dec 2000 06:10:15 -0600 I did not feel anything here in Linn Co. At 10:32 PM 11/30/00 -0600, you wrote: >Hi everyone! > >Has anyone picked up any earthquake activity in or around Iowa this >evening? A friend of mine who's a TV meteorologist just emailed me to >report a swarm of calls reporting a tremor. > >Mike Lozano > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: HELP From: "Ted Blank" ted@.......... Date: Fri, 1 Dec 2000 08:03:07 -0500 Fun part? The fun part is when you are duct-taping all the doors and windows in your house trying to get rid of that last draft of air. :-) When you make your cover put some plastic-covered peep holes in it so you can see whether the boom is still centered without lifting the lid. Soft foam around the bottom is great for sealing out drafts too. Regards, Ted Blank (ted@........... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: HELP From: "Larry Conklin" lconklin@............ Date: Fri, 1 Dec 2000 09:24:42 -0500 I am also a beginner at this sport. I have had a SG sensor running since June. I guess I'm a slow learner, but I just can't belive how sensitive the darn thing is. I have had the sensor covered from the beginning, and the interior of the enclosure is stuffed tight with laminated cardboard to eliminate the last shred of free air space. What I didn't do until recently was to seal the bottom of the enclosure to prevent air currents getting under the edge of the cover. The other day I finally got around to packing a couple of rags around the bottom of the cover. The result was the complete elimination of the major component of my background noise, which showed up as a signal with an average period of around 25 seconds. It cut my overall noise level by more than half. My other problem, which probably doesn't have a solution that doesn't involve pouring concrete into a hole in the back yard, is that there isn't any place in my basement that is sufficiently isolated from foot traffic on the floor above. The best compromise is a spot under the bedroom, but I have a very accurate record of when we go to bed and get up in the morning every day. Larry Conklin lconklin@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: oh boy... From: "Kareem Lanier" kareemjupiter@............. Date: Fri, 1 Dec 2000 07:01:40 -0800 It sounds like building a Lehman is going to be a lot of fun. Kareem Lanier Discover and Explore! www.kareemjupiter.com Subject: Re: HELP From: BOB BARNS roybar@........ Date: Fri, 01 Dec 2000 10:22:58 -0500 Hi, I would reiterate the other replies in stating the importance of a well insulated box. All long period sensors are extremely sensitive to air currents and tilting. As a final touch, add a heater, say 10 watts, to the inside of the top of the box. This will stagnate the air in the box and eliminate convection currents. This can be as simple as a resistor powered by a wall-wart. A small lamp running at half its rated voltage (for nearly infinite life) will also work. My rig works exactly like Conklin's--my basement floor bends when there is foot traffic in the bedroom above. This tilts the sensor. Since these signals don't look anything like a 'quake, just ignore them. I think that a good way to set the gain is to adjust it until you get +/- 10-20 counts on the quietest days. Larry's amp has a low-pass filter which has a cutoff frequency which is much too high for good signal/noise performance with a Lehman. I suggest adding a 6 or 8 pole filter with a cutoff of about 0.1Hz. This will reduce the noise due to microseisms which peak at about 0.16 Hz. Filter design is well described in Lancaster's book, see www.tinaja.com Bob Barns > Bryan & Regina Goss wrote: > > Ok I got my seismograph built and I used Larry's A/D card and > filter/amp, My question is how do I know if I have to much gain? > It looked as if I did so I put 15k res at r29 this reduced noise but I > don't know if it was to much. I can walk across my shop floor > 30x 40x concrete slab and going to seismograph I see the trace go up > about an inch then slowly go back to center when I walk away just the > opposite, The trace seems to drift up and down a little guess this is > normal?????? > I really need help > > this is before the damper and cover > http://www.tsixroads.com/~spardue/seismograph/seismograph.htm > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HELP From: "Ted Blank" ted@.......... Date: Fri, 1 Dec 2000 10:39:01 -0500 Has anybody tried taking a concrete saw and isolating a square of the floor in the corner of their basement? (Best done while the wife is shopping I imagine). Would this really have any benefit or would the bending stresses just be transmitted via the packed earth to the "floating" square? Regards, Ted Blank (ted@........... IBM Global Services - Performance Management and Capacity Planning at the Washington Systems Center Office: 238 Highland St., Portsmouth, N.H. 03801 Tieline: 8-253-9969 Outside: (603) 433-9201 Cellphone: (603) 512-4841 Office Fax: (603) 433-9190 Pager: 1-800-759-8888 PIN 1151100 Notes: Ted Blank/Portsmouth/IBM@IBMUS __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: mb - Ms disciminant From: John Taber taber@............. Date: Sat, 2 Dec 2000 04:46:07 +1300 (NZDT) Richard, You can find a reasonable description of mb and Ms in the textbook "Modern Global Seismology" by Lay and Wallace, though they don't give an illustration of actually calculating the magnitudes. They do reference two papers which probably would give examples (I haven't read the papers myself): Veith and Clawson, 1972, Magnitude from short period P wave data, Bull. Seismological Soc. Am., V. 62, 435-452. Geller, 1976, Scaling relations for earthquake source parameters and magnitudes, Bull. Seismological Soc. Am., V. 66, 1501-1523. Regards, John Taber From: "Richard J. Warburton" To: Sent: Friday, November 24, 2000 2:43 PM Subject: mb - Ms disciminant > Dear Larry, > I manufacture a very stable gravity meter (the 'Superconducting > Gravimeter'), which is very low noise up to about 1 mHz. Until > recently, I have not been much interested in higher frequencies, since > the range of frequencies from 1 mHz to 10 Hz seemed well covered by > other long period seismometers. Now, I believe that I might be able to > improve the 'SG' so that it could improve measurements in the 1 to 20 > mHz range. > > My knowledge of seismology is limited, but I know that the measurement > of mb-Ms is an important discriminant for separating underground > explosions from earthquakes. However, I have not yet found a simple and > clear explanation of how either mb or Ms is measured. What would be > most helpful would to find the exact definition of mb and Ms, and then > as an example show the incoming seismic wave train, the spectrum of the > wave train, and an illustration of the calculation of these two. > Advanced mathematics is okay as long as the result is "clarified" with > some examples. > > Is this available is any book or paper that you are aware of? > > Thanks much, > > Richard > > -- > Richard Warburton > GWR Instruments, Inc. > 6264 Ferris Square, Suite D > San Diego, California 92121 > phone: (858) 452-7655 > fax: (858) 452-6965 > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More Help From: "Bryan Goss" bgoss@.................. Date: Fri, 1 Dec 2000 11:03:43 -0600 Thanks, I will put up new pic this weekend I have already built a = plexa glass box. It is air tight except for at the bottom 1/8 inch gap = in some places. The box was almost as hard to build as the seismograph, = but I can see the seismograph:> When I first got the thing going with no = adjustment and gain at 2000. The noise was off the scale so I put in = extra resistor to reduce the Gain a lot more. I don't know how much. Ok = when you install SDR it takes about "just guessing" 60 sec to go across = the screen then drops down 2 more times then clears and starts over can = I change the time scale here this would make it so I would not see as = much drift/noise?? I have a lot to learn so please be patient with me.
 
  Thanks, I will = put up new=20 pic this weekend I have already built a plexa glass box. It is air tight = except=20 for at the bottom 1/8 inch gap in some places. The box was almost as = hard to=20 build as the seismograph, but I can see the seismograph:> When I = first got=20 the thing going with no adjustment and gain at 2000. The noise was off = the scale=20 so I put in extra resistor to reduce the Gain a lot more. I don't know = how much.=20 Ok when you install SDR it takes about "just guessing" 60 sec to go = across the=20 screen then drops down 2 more times then clears and starts over can I = change the=20 time scale here this would make it so I would not see as much=20 drift/noise??

I have a lot to learn so please be patient with=20 me.

Subject: Re: HELP From: BOB BARNS roybar@........ Date: Fri, 01 Dec 2000 13:59:02 -0500 Ted, This would probably work. A method which involves less sawing of concrete would be to drill three holes in the floor, say 2" in diameter, placed approx. under where the feet on the seismometer will be. This would be rather easy using a hole saw. Then, drive pipe into the underlying ground in such a way that the pipe does not touch the sides of the hole in the floor. Use, for example, 1" OD pipe. Then support the seismometer on the tops of the three pipes. I'll bet that the isolation from floor bending would be very good. When the attraction of amateur seismometry pales (or if the holes become geysers) , it would be easier to cement up the holes than if a big square had been cut out. Bob Barns Bob Barns Ted Blank wrote: > > Has anybody tried taking a concrete saw and isolating a square of the floor > in the corner of their basement? (Best done while the wife is shopping I > imagine). Would this really have any benefit or would the bending stresses > just be transmitted via the packed earth to the "floating" square? > > Regards, > Ted Blank (ted@........... > > IBM Global Services - Performance Management and Capacity Planning at the > Washington Systems Center > Office: 238 Highland St., Portsmouth, N.H. 03801 > Tieline: 8-253-9969 Outside: (603) 433-9201 > Cellphone: (603) 512-4841 Office Fax: (603) 433-9190 Pager: > 1-800-759-8888 PIN 1151100 > Notes: Ted Blank/Portsmouth/IBM@IBMUS > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HELP From: twleiper@........ Date: Fri, 1 Dec 2000 18:15:25 -0500 On Fri, 1 Dec 2000 10:39:01 -0500 "Ted Blank" writes: > > Has anybody tried taking a concrete saw and isolating a square of > the floor > in the corner of their basement? (Best done while the wife is > shopping I > imagine). I did that as a teenager and my father promptly curtailed my pusuit of amateur seismology. Our basement had a raised section due to a immovable (without blasting) rock or bedrock. I "isolated" my slab but only got about a weeks worth of comparative data before my Lehman (back then we called them "garden gate") instrument was "dismantled" by being hurled at the cinder block wall. If you are one who filters for teleseismic events, this is a waste of time. However if parking the car tilts things, you might consider it. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Reply soon I am ready toget started From: "Bryan & Regina Goss" bgoss@.................. Date: Fri, 1 Dec 2000 18:44:23 -0600 Could someone tell me recommended settings for sdr x and y scale? and = how do I know how big the wave is when I walk across the floor, I was = told 10 is good how do I know How big it is?
Could someone tell me recommended = settings for sdr=20 x and y scale? and how do I know how big the wave is when I walk across = the=20 floor, I was told 10 is good how do I know How big it is?
 

 

Subject: cut slab for pier From: sean@........... Date: Fri, 1 Dec 2000 20:31:02 -0600 (CST) Ted, Here is a repeat of a note on the subjects from about a year ago: Regarding sawing up the slab floor: our experience: We have an IRIS station just west of Nashville at Waverly, TN (WVT) at a TN div of geology drilling core storage facility. To make the original pier, we had a contractor saw a double slit around a 5 ft x 10 ft piece of the floor and remove the concrete between the slits that were 4" apart. This effectively isolated the "pier" from most local noise, although we would still get many event triggers when the geologists were playing with their rocks. But serious horizontal tilt noise was still a problem for the STS-1 seismometers operating at 360 seconds. So we got $5k from IRIS and had the slab pier removed, and dug a pit 6 ft deep to a more consolidated clay layer (bedrock is 30 ft down), and filled the pit with concrete back up to the floor level. THe gap between the pier and the floor was filled with tar (a bad idea!: we had to cover it with ethofoam to keep it off of everything). The new pier reduced the horizontal noise by greater than a factor of 10. A note on such piers and the idea of putting pipes thru the floor to support a pier: don't make an inverted pendulum. The depth of the arrangement should generally be no more than its smallest horizontal dimension. Even in consolidated clays it could wobble around. And remember that a horizontal seis is sensitive to tilt noise as the square of the operating period, whereas a vertical is not. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: HELP From: Nick & Sophie Caporossi nickcap@............. Date: Fri, 01 Dec 2000 22:04:54 -0500 At 09:24 AM 12/1/00 -0500, you wrote: >The best compromise is a spot under the bedroom, but I >have a very accurate record of when we go to bed and get up in the morning >every day. > >Larry Conklin >lconklin@............ > Hi Larry Conklin: I had the same problem. I was able to reduce the ground noise considerable by moving the sensors to the middle of the basement. It seems that the out side walls of the house which rest on the foundation has a lot to do with making the basement floor wiggle. The center of basement is like being in the middle of a see-saw. Nick __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mb - Ms ratio From: sean@........... Date: Fri, 1 Dec 2000 21:22:13 -0600 (CST) Richard, Regarding Mb and Ms discrimination of nuclear testing: a very simple explanation can be offered: Mb is the "body wave" magnitude, and is generally derived from the amplitude/distance measurements of the P or S wave after they have traveled through the "body" of the earth., which is a compressional wave radiating out from the seismic source. Note that the polarity of this wave can be negative: ie dilatational, if your station is located in that quadrant of the focal mechanism. Ms is the surface wave magnitude, generally derived from the Lg type waves, which are usually the largest peak to peak amplitude of the seismic record. These are generated when the body waves reach the free surface, and most of their energy comes from the S-waves. The formulas for determining Mb or Ms are similar, only differing in the path attenuation parameters. A generic form for Ms is Ms = log(A/T) + 1.66*log(delta) + 0.18; A in nanometers, T in seconds, and delta in degrees. Many a PhD thesis has been argued over the values of the constants, some of which end up "my quakes are bigger than yours, so WE should get the funding". For discriminating nuclear tests, the main difference between these and earthquakes is the focal mechanism, or what happens at the source of the event. With a quake, the mechanism is one side of a fault segment moving laterally or vertically with respect to the other side, over a rupture length that is proportional to the quake magnitude. The source is a "double couple" that releases about equal P and S wave energy in a pattern that is a symmetric but mirrored image about the fault. But an explosion is a "point source" that radiates mostly compressive energy equally in all directions. Nuclear tests do not generate shear waves, so they produce minimal surface waves. (Strip mine blasts DO produce large surface waves because of the ripple in the firing). The Nevada Test Site underground tests were always remarkable in our records because of the energetic P phase, no S phases, and a wimpy surface wave. (A further give-away of an NTS event was that they always occurred exactly on the UTC hour.) SO one of the promising methods for policing the CTBT (test ban treaty) was hoped to be the Mb to Ms ratio. However, this is greatly affected by the ray paths, and setting off a small nuke off center in a large oblong cavity can imitate a double couple with shear and surface waves. Often the blast will release local strain, showing a shear wave. By the way, I don't think the improving the S/N of your SG in the range from 1 to 20 mhz (1000 to 50 seconds range) would help in this regard, since the period of body waves (P and S) are relatively short, in the range from 1 to 10 seconds at teleseismic distances. Regards, Sean-THomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake Reports From: "Larry Cochrane" cochrane@.............. Date: Fri, 1 Dec 2000 19:59:24 -0800 Dick, I'm not sure how WinQuake could directly access the DMC and USGS QED databases? WinQuake currently uses the UNIX finger service and a few HTML pages to access the event lists. I just finished adding two new event lists to the Event Report feature of WinQuake. They are http://gldss7.cr.usgs.gov/neis/qed/qed.html and http://quake.wr.usgs.gov/cgi-bin/quake/seismo.nrcan.gc.ca. I hope to have a beta release ready in a week or so. One thing I have been thinking about is to contact Alan Jones too see if WinQuake could use the near real-time database used by his SeisVol program. The new version of SeisVol has the ability to access an event database over the net. I believe the database is at binghamton.edu. -Larry ----- Original Message ----- From: "Dick Webb" To: Sent: Friday, November 24, 2000 9:19 AM Subject: Winquake Reports > Hi, > > I use Winquake and it's Event Report feature but have not been able to set > it up to download either IRIS DMC or USGS qed data. I looked at the help > files but could not figure out how to apply them. Have any of you had any > luck. My specific need is to access files older that those in the NEIC > Near Real Time report (which works well for me). > > Dick __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mb - Ms ratio From: ChrisAtUpw@....... Date: Fri, 1 Dec 2000 23:04:40 EST Hello Richard, Have a look at http://www.nemre.nn.doe.gov/nemre/ for a start. Explosions generate a different shape of "wave packet" to earthquakes, both in seismic and infrasonic measurements. Quite a lot of work has been done on trying to separate the two, since it is a bit critical for CTBT monitoring. Sorry, but I am not familiar with your abbreviations. What temperature does your superconducting instrument run at, just out of curiosity? I did some low temperature physics. I tried to find a Website for you but failed. Hope that this is of some help. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: mb - Ms disciminant From: The Lahrs johnjan@........ Date: Fri, 01 Dec 2000 21:14:57 -0700 Richard, See the IASPEI Manual of Seismological Observatory Practice for details on computing magnitudes. This covers Local (ML), Surface (MS) and Body Wave (mb) magnitudes. The 1979 version: http://www.seismo.com/msop/msop79/par/par.html may be easier to follow than the "new" version: http://www.seismo.com/msop/nmsop/03%20source/source4/source4.html John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: calibration info From: The Lahrs johnjan@........ Date: Fri, 01 Dec 2000 22:04:36 -0700 Dave, I'm glad that you have a system working with AmaSeis software. Could you post the schematic and parts list for your electronics/AD and also make your version of AmaSeis available? I think others might find it quite useful. John At 12:22 PM 11/19/00 , you wrote: >... My home brew >electronics board only has 3 chips: one low noise opamp, one switched >capacitor 8 pole bessel filter chip, and one PIC microprocessor >with built-in 16 bit adc and serial output ports. I run a serial cable to >my PC directly from the mpu, and system power (~3ma) is drawn from >the serial port. I log the serial data at 16 sps with the Amaseis freeware >which can produce files for input to WinQuake. My data logging >computer is an old P90 that simultaneously runs SETI@HOME and >is used for other odd jobs, so Amaseis does not seem to be using >much of its resources. > >Caio, > >Dave Saum John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Reply soon I am ready toget started From: "Larry Cochrane" cochrane@.............. Date: Fri, 1 Dec 2000 21:17:55 -0800 Bryan, SDR's X and Y scales are for display purposes only. They do not effect = the data that gets stored to disk or the data in the event files = generated from the data that gets stored to disk. For the X scale it = depends on how much time you want to display on the screen. I use 80. = For the Y scale it depends on the number of lines you are displaying and = sensitivity of the sensor. Once you get things going you will need to = play around with these settings and set them to your liking. -Larry Cochrane Redwood City, PSN ----- Original Message -----=20 From: Bryan & Regina Goss=20 To: psn-l@................. Sent: Friday, December 01, 2000 4:44 PM Subject: Reply soon I am ready togged started Could someone tell me recommended settings for sdr x and y scale? and = how do I know how big the wave is when I walk across the floor, I was = told 10 is good how do I know How big it is?
Bryan,
 
SDR's X and Y scales are for display = purposes only.=20 They do not effect the data that gets stored to disk or the data in the = event=20 files generated from the data that gets stored to disk. For the X scale = it=20 depends on how much time you want to display on the screen. I use 80. = For the Y=20 scale it depends on the number of lines you are displaying=20 and sensitivity of the sensor. Once you get things going you will = need to=20 play around with these settings and set them to your = liking.
 
-Larry Cochrane
Redwood City, PSN
 
----- Original Message -----
From:=20 Bryan=20 & Regina Goss
Sent: Friday, December 01, 2000 = 4:44=20 PM
Subject: Reply soon I am ready = togged=20 started

Could someone tell me recommended = settings for=20 sdr x and y scale? and how do I know how big the wave is when I walk = across=20 the floor, I was told 10 is good how do I know How big it = is?
 

 

Subject: Re: HELP From: "Larry Conklin" lconklin@............ Date: Sat, 2 Dec 2000 10:30:41 -0500 Nick, I tried the middle of the floor also, but it didn't help much. My basement has been partitioned off into three separate rooms. The interior walls and the ground floor support columns are distributed in such a way that I don't have a spot that is very far from something that connects to the floor above. One of the many things that continues to supprise me is how small a move from one location to another can result in a significant difference. There is probably a really quiet "node" somewhere, but it would take a long time to find out. One of the other things I've learned is that if I move the thing, it can take several days to stabalize, during which time I typically see occasional big transients and I have to tweak the leveling at least once a day for a week or more before things settle down. Larry ----- Original Message ----- From: "Nick & Sophie Caporossi" To: Sent: Friday, December 01, 2000 10:04 PM Subject: RE: HELP > At 09:24 AM 12/1/00 -0500, you wrote: > >The best compromise is a spot under the bedroom, but I > >have a very accurate record of when we go to bed and get up in the morning > >every day. > > > >Larry Conklin > >lconklin@............ > > > Hi Larry Conklin: > I had the same problem. I was able to reduce the ground noise considerable > by moving the sensors to the middle of the basement. It seems that the out > side walls of the house which rest on the foundation has a lot to do with > making the basement floor wiggle. The center of basement is like being in > the middle of a see-saw. > > Nick > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Meet me in SFO From: The Lahrs johnjan@........ Date: Sat, 02 Dec 2000 13:24:54 -0700 How would it be to meet at: Tommy's Joynt at the corner of Geary and Van Ness. on Saturday night, December 16, 6:30 PM? This restaurant has good food at a reasonable price and is not so crowded that we would have problems finding a table or two. Just a suggestion to get the ball rolling! Cheers, John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Meet me in SFO From: steve hammond shammon1@............. Date: Sat, 2 Dec 2000 21:13:09 -0800 Hi John, I think this would be a good idea. I have had a two notes from others so they should respond here if they want to meet and have dinner together. Judging from the response I have seen, it would be better to try to have a larger PSN meeting in April as suggested. The weekend of the 15th / 16th is just too close to Christmas for many. Regards, Steve Hammond -----Original Message----- From: The Lahrs [SMTP:johnjan@......... Sent: Saturday, December 02, 2000 12:25 PM To: psn-l@.............. Subject: Meet me in SFO How would it be to meet at: Tommy's Joynt at the corner of Geary and Van Ness. on Saturday night, December 16, 6:30 PM? This restaurant has good food at a reasonable price and is not so crowded that we would have problems finding a table or two. Just a suggestion to get the ball rolling! Cheers, John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: alarm page From: Norman Davis wb6shi@........ Date: Sun, 03 Dec 2000 07:09:05 -0800 I use to have link to a web page that had an alarm setup on it and if = there was a quake it would alert you to it. Is it still around and = where?
I use to have link to a web page that = had an alarm=20 setup on it and if there was a quake it would alert you to it. Is it = still=20 around and where?
 
Subject: Re: alarm page From: The Lahrs johnjan@........ Date: Sun, 03 Dec 2000 09:01:14 -0700 H Norm,

You can try this page:
http://geohazards.cr.usgs.gov/fingview/

It includes a Java-based alarm window.  I can't guarantee that it works all of
the time, as there are still mysteries related to Java that are beyond me, but
you can give it a try.

It will work if you make the alarm window small, but apparently goes to
sleep if you minimize the window.

Cheers,
John

At 08:09 AM 12/3/00 , you wrote:
I use to have link to a web page that had an alarm setup on it and if there was a quake it would alert you to it. Is it still around and where?
 

John C. Lahr
1925 Foothills Road
Golden, CO 80402
(303) 215-9913
john@........
http://lahr.org/john-jan/science.html Subject: long period seis orientation From: sean@........... Date: Sun, 3 Dec 2000 14:58:50 -0600 (CST) Regarding locating a long period horizontal seis in a basement. Orientation of the sensitive axis: The LP seis is sensitive to floor/pier tilt in the direction that the mass moves, which is at right angles to the boom. So to minimize local tilt where a single instrument is involved, one has to orient the sensor so that the boom is at a right angle to the suspected tilt direction. Most LP "garden gate" seismometers are rectangular in design, so it is convenient to place the long axis of the box against the basement wall. This then has the mass moving towards or away from wall, which is the undesirable direction of greater floor tilting. If you can imagine the floor tilting as a slab with one edge fixed at a hinge, the foundation wall is the hinge. The LP seis sensitive axis should be at a right angle to this hinge. This means that the boom axis, or longer axis of the box, will extend out from the wall. A further reduction of slab deformity noise is realized if the transverse leveling or mass centering screws are at the mass end of the boom and closest to the wall. I am operating a prototype of the VBB-BBT (very broadband beam balance tiltmeter) in the basement of the farmhouse here. The east basement wall has been reinforced with cinderblock because of added floor beams since termites devoured the ends of the joists in the '40s. The room used to be the coal bin, so the floor is competent. The BBT is installed close to this wall, immediately in front of the pier for the VBB vertical shown in a photo on the web site, on a 1" high "pier" made with grouted ceramic tiles. The sensitive axis, the axis of the beam, is parallel to the wall, so going down and sitting beside it results in a tilt of only about 0.6 microradian, whereas today the barometric loading noise is running about 1 microradian P-P at a period of around 240 seconds. The BBT still senses large trucks on the street about 30 m away and parallel to the wall, with of the tilt impulse indicating the direction of travel at the 0.1 to 0.3 microradian level. Hopefully this will help you get quieter data from your LP horizontal seismometers. As always, I encourage the construction of vertical sensors, since they are relatively immune to pier tilt. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: CORRECTED long period seis orientation From: sean@........... Date: Sun, 3 Dec 2000 15:05:43 -0600 (CST) As soon as I posted this note, I saw a serioius error: here is the corrected version. Delete the first version. Regarding locating a long period horizontal seis in a basement. Orientation of the sensitive axis: The LP seis is sensitive to floor/pier tilt in the direction that the mass moves, which is at right angles to the boom. So to minimize local tilt where a single instrument is involved, one has to orient the sensor so that the boom motion is at a right angle to the suspected tilt direction, ie. the boom axis is is in the direction of the tilt. Most LP "garden gate" seismometers are rectangular in design, so it is convenient to place the long axis of the box against the basement wall. This then has the mass moving towards or away from wall, which is the undesirable direction of greater floor tilting. If you can imagine the floor tilting as a slab with one edge fixed at a hinge, the foundation wall is the hinge. The LP seis sensitive axis should be at a right angle to this hinge. This means that the boom axis, or longer axis of the box, will extend out from the wall. A further reduction of slab deformity noise is realized if the transverse leveling or mass centering screws are at the mass end of the boom and closest to the wall. I am operating a prototype of the VBB-BBT (very broadband beam balance tiltmeter) in the basement of the farmhouse here. The east basement wall has been reinforced with cinderblock because of added floor beams since termites devoured the ends of the joists in the '40s. The room used to be the coal bin, so the floor is competent. The BBT is installed close to this wall, immediately in front of the pier for the VBB vertical shown in a photo on the web site, on a 1" high "pier" made with grouted ceramic tiles. The sensitive axis, the axis of the beam, is parallel to the wall, so going down and sitting beside it results in a tilt of only about 0.6 microradian, whereas today the barometric loading noise is running about 1 microradian P-P at a period of around 240 seconds. The BBT still senses large trucks on the street about 30 m away and parallel to the wall, with of the tilt impulse indicating the direction of travel at the 0.1 to 0.3 microradian level. Hopefully this will help you get quieter data from your LP horizontal seismometers. As always, I encourage the construction of vertical sensors, since they are relatively immune to pier tilt. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Regarding noise From: n0cwr@......... Date: Mon, 04 Dec 2000 12:27:26 +0000 Regarding the location in the basement. Is it possible you have to consider more than just noise from above the basement to be concerned with. On windy days my noise floor rises. This could be due to the motion of the house, but what about the two 50-60 foot trees in my yard? Could they be a factor? I don't receive a lot of street traffic night or day on the street in front of my house. But my noise level appears higher on any given daytime as compared to the early hours of the morning whether anyone is at home or not. When they were doing construction blocks away on a road, I swear I could see the "bucket spikes" as they busted and removed concrete slabs. I would imagine those that live in the country have lower noise levels. The more secluded the better. Is this possible? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meet me in SFO From: John Hernlund hernlund@............ Date: Mon, 04 Dec 2000 12:54:48 -0800 steve hammond wrote: > Hi John, I think this would be a good idea. I have had a two notes from > others so they should respond here if they want to meet and have dinner > together. Judging from the response I have seen, it would be better to try > to have a larger PSN meeting in April as suggested. The weekend of the 15th > / 16th is just too close to Christmas for many. > Regards, Steve Hammond > > -----Original Message----- > From: The Lahrs [SMTP:johnjan@......... > How would it be to meet at: > Tommy's Joynt at the corner of Geary and Van Ness. > > on Saturday night, December 16, 6:30 PM? This restaurant has > good food at a reasonable price and is not so crowded that we would > have problems finding a table or two. > > Just a suggestion to get the ball rolling! Sounds like a plan. I cannot guarantee that I'll be there, but I'll do my best to make it! Although I am there for the whole meeting, I'll be busy meeting with people on some of the projects I am currently working on. Cheers! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: noise and sensitivity From: sean@........... Date: Mon, 4 Dec 2000 15:31:33 -0600 (CST) Some more comments on long period noise. First, I think that everyone on the list would be better able to understand the problem if you started a query about your own seismometer by briefly describing it. eg: "I am operating a Lehman with a 15 second period." If you are asking about amplification, etc, describe the coil/ magnet constant, damping, and amplifier gain. These would help others relate to your enquiry. eg: "The 1000 ohm coil has a constant of 25 Volts/m/sec and is damped at critical with at 1500 ohm resistor, etc." Speaking of damping: dash-pot (oil, air) damping was used only on completely mechanical seismometers like the Wiechert. Once electromagnetic generator coils and galvanometers were used, resistive damping was used, although some copper vane/eddy current arrangements were still used to avoid loss of the weak output if the early iron magnets. With restive damping, the EXACT amount can be calculated, rather than trying to fit curves and over-swing ratios, which generally involves visible motion of the mass which is actually not characteristic of the micron to sub-micron motion of real quakes, since the linearity approximations become small arcs, both vertical and horizontal for a horizontal "garden gate" seis. A resistive damping value about equal to the coil resistance gives a broad overdamped response that will make the seis sensitive to P and S waves as well as much longer surface waves. THis will make the seis sensitive to both near field (lt. 500 km) events as well as teleseismic events. However, this causes a loss of half the signal voltage: the output is proportional to [Rd / (Rc + Rd)], where Rd is the damping R, and Rc is the coil R. However, a loss of 6db (50%) is no problem for modern amplifiers, whose gain switches usually select in 6db (x2) steps. All the long period (Sprengnether S5100) seismometers that I currently operate have 500 ohm coils damped with a 500 ohm resistor. This results in a semi- broadband response (a broad arc of about 20db (x 10) amplitude) from 1 second to 60 seconds for a 15 second Tn seis. Someone mentioned having the seis overswing of more than one cycle. This is not damping at all, and results in a response that is very peaked at the natural period, and greatly reduced elsewhere. It will be sensitive mostly at the mechanical period, like for teleseismic surface waves (and local tilt noise), with little sensitivity to everything else. A critically or, better, an overdamped seis is much less sensitive to tilt noise, since the causative transient will usually pass before the seis has responded very much. Regarding recording sensitivity: if you aren't seeing the 6-second microseism background, you won't see many quakes. Of course this varies by your location; most are induced by low pressure storms off the northeastern continental shelf, and propagate through the eastern USA upper crust with little attenuation. Today at St. Louis they are running about 5 millivolts P-P from the VBB-STM seis with an output of 1600 Volts/m/sec, or 1.6 mv/micron/sec. So the amplitude at 6 seconds is about 3 microns. During storms they may be 10 times this. This is with a digitizer of 200 mv full scale and 0.1 mv least count. So setting the amplifier gain depends on your coil constant and the range of your digitizer. If the constant is 50 V/m/sec, and the amplifier gain is 100 (40db), this is 5 millivolts/micron/second. A 10 volt full scale 16 bit digitizer has a least count value of 0.3 millivolts. So the sensitivity is 16 counts/micron/second, and a 3 micron P-P 6-second microseism will be about 50 counts P-P. Of course, if your coil constant is only 5 V/m/sec, the microseisms are only 5 counts, and you might have to use 10x more gain to see them with any resolution. Regarding noise on windy days. With an un-enclosed vertical, this is mostly mass buoyancy in the barometric pressure variations. With a long period horizontal, the noise is due to tilting because of differential loading of the surface of the earth due to the gradients in the barometric pressure that are causing the wind. Wind blowing on trees makes both vertical and horizontal surface waves but only in the very near surface, which is one reason why installing the sensor at 3 m or greater depth is a big improvement. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake Reports From: Dick Webb dwebb2@.............. Date: Mon, 04 Dec 2000 20:28:20 -0500 Larry, Thanks, that is exactly what laggards like me need. Access to some of the files older than 1-2 weeks. Dick At 07:59 PM 12/01/2000 -0800, you wrote: >Dick, > >I'm not sure how WinQuake could directly access the DMC and USGS QED >databases? WinQuake currently uses the UNIX finger service and a few HTML >pages to access the event lists. I just finished adding two new event lists >to the Event Report feature of WinQuake. They are >http://gldss7.cr.usgs.gov/neis/qed/qed.html and >http://quake.wr.usgs.gov/cgi-bin/quake/seismo.nrcan.gc.ca. I hope to have a >beta release ready in a week or so. > >One thing I have been thinking about is to contact Alan Jones too see if >WinQuake could use the near real-time database used by his SeisVol program. >The new version of SeisVol has the ability to access an event database over >the net. I believe the database is at binghamton.edu. > >-Larry > > >----- Original Message ----- >From: "Dick Webb" >To: >Sent: Friday, November 24, 2000 9:19 AM >Subject: Winquake Reports > > > > Hi, > > > > I use Winquake and it's Event Report feature but have not been able to set > > it up to download either IRIS DMC or USGS qed data. I looked at the >help > > files but could not figure out how to apply them. Have any of you had any > > luck. My specific need is to access files older that those in the NEIC > > Near Real Time report (which works well for me). > > > > Dick > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: noise From: "Bryan & Regina Goss" bgoss@.................. Date: Mon, 4 Dec 2000 23:20:38 -0600 Ok here is an odd request, I have a Lehman with a 18 second period before the magnetic damper I think it is working I have only had it going for about 2 days but nothing has happened big enough for me to see or I don't know what to look for,Anyway here is the question. Can someone send me a file with a good 6-second microseism background noise. I live Mississippi and I guess this is what I should be seeing, this is a pic of 1 Min of time. http://www.freedom2000net.com/userpages/bgoss/min.jpg __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: noise From: "Larry Conklin" lconklin@............ Date: Tue, 5 Dec 2000 11:24:38 -0500 I would be very interested in this also. Perhapse someone could post a file on Larry's site and let us know the file name. Larry Conklin lconklin@............ ----- Original Message ----- From: "Bryan & Regina Goss" To: Sent: Tuesday, December 05, 2000 12:20 AM Subject: Re: noise > Ok here is an odd request, I have a Lehman with a 18 second period before > the magnetic damper > I think it is working I have only had it going for about 2 days but nothing > has happened big enough for me to see > or I don't know what to look for,Anyway here is the question. Can someone > send me a file with a good 6-second microseism background noise. I live > Mississippi and I guess this is what I should be seeing, this is a pic of 1 > Min of time. > http://www.freedom2000net.com/userpages/bgoss/min.jpg > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: noise From: Karl Cunningham karlc@....... Date: Tue, 05 Dec 2000 08:46:58 -0800 I have a file on my web site that you can view: http://www.jps.net/karlc/6secnoise.gif For scale you can distinguish individual bits of the A/D in some parts of the waveform. Karl Cunningham At 11:20 PM 12/4/2000 -0600, you wrote: >Ok here is an odd request, I have a Lehman with a 18 second period before >the magnetic damper >I think it is working I have only had it going for about 2 days but nothing >has happened big enough for me to see >or I don't know what to look for,Anyway here is the question. Can someone >send me a file with a good 6-second microseism background noise. I live >Mississippi and I guess this is what I should be seeing, this is a pic of 1 >Min of time. >http://www.freedom2000net.com/userpages/bgoss/min.jpg __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Unknown Seismometer From: Karl Cunningham karlc@....... Date: Tue, 05 Dec 2000 13:36:07 -0800 Hello -- I am interested in identifying an old piece of equipment that I think is a vertical seismometer. A picture is at: http://www.keckec.com/seismo/images/unknown.jpg It is about 24 inches long (note Kinemetrics Ranger in background for scale), and has no labels or names anywhere on it. Through the window I can see a coil of wire (like a speaker voice coil), and the donut-shaped piece is magnetic. There are three boxes of electronics connected to it -- one appears to be an attenuator, another a filter, and another probably an amplifier. I would appreciate hearing anyone's comments about it. Thanks in advance, Karl Cunningham __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meet me in SFO From: John Taber taber@............. Date: Wed, 6 Dec 2000 11:08:13 +1300 (NZDT) John, Sounds good to me. John Taber > > -----Original Message----- > From: The Lahrs [SMTP:johnjan@......... > How would it be to meet at: > Tommy's Joynt at the corner of Geary and Van Ness. > > on Saturday night, December 16, 6:30 PM? This restaurant has > good food at a reasonable price and is not so crowded that we would > have problems finding a table or two. > > Just a suggestion to get the ball rolling! __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: noise From: "Bryan & Regina Goss" bgoss@.................. Date: Tue, 5 Dec 2000 20:31:54 -0600 00/12/04 04:43:09 UTC 14.87N 93.84W Depth: 33.0 km 5.7Ms NEAR COAST OF CHIAPAS, MEXICO 90 miles (140 km) S of Tonala, Chiapas, Mexico This is my file of what I think may be this Quake does this look right? http://www.freedom2000net.com/userpages/bgoss/mexico57.jpg __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise From: "David Saum" DSaum@............ Date: Wed, 6 Dec 2000 11:08:32 -0500 I suggest that noise examples need an fft with a frequency scale attached in order to tell whether the noise is around 6 seconds period. Winquake can provide this. How about the noise example I posted last month? Here it is again with both velocity and fft data. http://www.infiltec.com/seismo/nois-amp.gif velocity adc data http://www.infiltec.com/seismo/nois-fft.gif fft spectra Although the velocity adc data does not show any obvious periodicity, the fft does. The data is from my 18 sec Lehman with oil bath damping. There seems to be a peak in the spectra near f=0.2 or 5 sec. How broad should the 6 sec noise spectral peak be? Or am I just looking at the frequency response of my system filtering random noise? TIA, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Bigquake working? From: Jeff Batten jeff.batten@........ Date: Wed, 06 Dec 2000 10:05:22 -0800 Hello, I have not received a Bigquake email in a few weeks. Anyone else get a report? Thanks Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 6 second microseisms From: sean@........... Date: Wed, 6 Dec 2000 13:41:03 -0600 (CST) Dave, Regarding the 6 second microseisms: Nothing special should be needed to observe the microseisms in the data from a long period instrument that is properly damped, has sufficient protection from noise, and sufficient gain to record moderate quakes. The Ms 5.7 in Mexico on Dec. 04 had P-wave amplitudes about 10x the (unfiltered) 6-second microseisms at the time (at St. Louis). They are very clear and monochromatic in period, so much so that I have used passive twin-T notch filters for years to remove them from analog monitor records at the observatory. An analysis of the average period at St. Louis showed 6.2 seconds to be the optimum period to design the filter for. The notch filter reduces the microseisms by over 40 db (factor of 100) to improve the readability of the record. A notch here between the VBB-STM and the analog drum makes them disappear for most of the time. They are very clear sine waves on a long period record: simply count the peaks or number of sine waves between minute marks: sometimes there are 9, mostly 10, or sometimes 11. A FFT of the LP data should show the microseism peak an average of about 40 db above the noise level at 20 seconds or so. Regards, Sean-Thomas ps: Jeff, BIGQUAKE is working; just received the report on the Mw 7.2 this AM in Turkmenistan. A very nicely dispersed surface wave train arrived here, starting at about 90 seconds period and rising to 20 seconds over about 15 minutes. You might have to re-subscribe. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Bigquake working? From: JD Cooley jdcooley@........ Date: Wed, 06 Dec 2000 16:03:01 -0800 It is working for me. "JD" Cooley At 10:05 AM 12/6/00, you wrote: >Hello, > >I have not received a Bigquake email in a few weeks. >Anyone else get a report? > >Thanks > >Jeff >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Drum Trace for New Britian Ms6.6 quake From: Arie Verveer ajbv@............ Date: Thu, 07 Dec 2000 09:29:51 +0800 Hi, This may be of interest: Drum Recording at (For 6 Dec 2000) http://www.iinet.net.au/~ajbv/ftp/Drum.html shows a good trace of the Ms 6.6 quake in New Britian region (PNG). The trace is updated every 1:10 UTC. 00/12/06 22:57:40 4.17S 152.81E 33.0 6.6Ms A NEW BRITAIN REGION, P.N.G. Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meet me in SFO From: Karl Cunningham karlc@.......... Date: Thu, 07 Dec 2000 06:30:30 -0800 Hi John -- Thanks for taking the initiative to organize the meeting. I plan to be there. As a suggestion, you might consider posting the meeting notice to the PSN list again early next week, along with a count of how many responses your've gotten so far. There may be some that are on the fence about going, who might be inspired to go if they see it's really going to happen. Thanks again, Karl Cunningham La Mesa, CA. karlc@.......... At 13:24 12/2/2000 -0700, you wrote: >How would it be to meet at: >Tommy's Joynt at the corner of Geary and Van Ness. > >on Saturday night, December 16, 6:30 PM? This restaurant has >good food at a reasonable price and is not so crowded that we would >have problems finding a table or two. > >Just a suggestion to get the ball rolling! > >Cheers, >John > > >John C. Lahr >1925 Foothills Road >Golden, CO 80402 >(303) 215-9913 >john@........ >http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: meet in SFO From: sean@........... Date: Thu, 7 Dec 2000 12:06:56 -0600 (CST) John, Even though I won't be there, I want to second your suggestion of Tommys Joynt for the PSN get-together. I have always enjoyed their hot buffet (the line forms at the door), especially their corned beef; I've never tried the Buffalo stew. They have a large table upstairs at the back that might be available; the first floor tables are already lined up for larger groups. Are reservations possible? Its a long walk from the Moscone Center: if someone would be willing to hold up a "PSN" sign at the top of the escalators at 6 PM, maybe several people who are staying nearby could share a taxi. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismic Event Dead Sea From: GeE777@....... Date: Thu, 7 Dec 2000 15:20:18 EST Hello, Is there any evidence of about a magnatude 4.7 seismic event in the Dead Sea area between Israel and Jordan in October or early November, 1999? Thank you for responding. George Erich Exploration Consultant e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: How do I upload my files?? From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 7 Dec 2000 19:23:29 -0600 I would like to upload EVANSVILLE,INDIANA . I got strong reading I am = 216 miles away how do I do this=20 and one more question How do I know where to Put the P and S markers?
I would like to upload = EVANSVILLE,INDIANA . I=20 got strong reading I am 216 miles away how do I do this
and one more question How do I know = where to Put=20 the P and S markers?
 
Subject: Re: Meet me in SFO From: John Hernlund hernlund@............ Date: Thu, 07 Dec 2000 17:33:48 -0800 > At 13:24 12/2/2000 -0700, you wrote: > >How would it be to meet at: > >Tommy's Joynt at the corner of Geary and Van Ness. > > > >on Saturday night, December 16, 6:30 PM? This restaurant has > >good food at a reasonable price and is not so crowded that we would > >have problems finding a table or two. > > > >Just a suggestion to get the ball rolling! Hey Y'all, It doesn't look like I am going to be able to be there...I have to go to a rock and mineral physics reception happening at precisely the same time! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic Event Dead Sea From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 7 Dec 2000 19:55:32 -0600 ----- Original Message ----- From: To: Sent: Thursday, December 07, 2000 2:20 PM Subject: Seismic Event Dead Sea > Hello, > Is there any evidence of about a magnatude 4.7 seismic event in the Dead Sea > area between Israel and Jordan in October or early November, 1999? > > Thank you for responding. > > George Erich > Exploration Consultant > e-mail GeE777@....... > 33 53.90N > 118 04.53W > http://hometown.aol.com/gee777/myhomepage/profile.html > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: link From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 7 Dec 2000 19:57:22 -0600 http://www.freedom2000net.com/userpages/bgoss/3.9.jpg Does this look good I am 216 miles from this 3.9
http://www= ..freedom2000net.com/userpages/bgoss/3.9.jpg
 
Does this look good I am 216 miles from = this=20 3.9
Subject: Meet me in SFO@Tommy's Joynt From: The Lahrs johnjan@........ Date: Thu, 07 Dec 2000 21:34:30 -0700 OK, let's do it!!!

Tommy's Joynt at the corner of Geary and Van Ness.
<http://www.sf gate.com/eguide/barguide/neighborhood4.shtml>
on Saturday night, December 16, 6:30 PM.  This restaurant has
good food at a reasonable price and is not so crowded that we would
have problems finding a table or two.  I'll bring some information
on the recently proposed US Educational Seismology Network
(USESN) to share.

As Sean suggests, those at the AGU meeting can meet at the top of
the escalators at 6 PM and share a taxi.

Confirmed so far are:
John Lahr
Karl Cunningham
John Taber
Steve Hammond

If you're going to be at the meeting or live anywhere nearby, you
won't want to miss this!  Please post your intentions so we will know
how large a table is required.

Cheers,
John


John C. Lahr
1925 Foothills Road
Golden, CO 80402
(303) 215-9913
john@........
http://lahr.org/john-jan/science.html Subject: Re: Meet me in SFO@Tommy's Joynt From: "Larry Cochrane" cochrane@.............. Date: Thu, 7 Dec 2000 20:43:44 -0800 Count me in.... -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: The Lahrs To: psn-l@.............. Sent: Thursday, December 07, 2000 8:34 PM Subject: Meet me in SFO@Tommy's Joynt OK, let's do it!!! Tommy's Joynt at the corner of Geary and Van Ness. on Saturday night, December 16, 6:30 PM. This restaurant has good food at a reasonable price and is not so crowded that we would have problems finding a table or two. I'll bring some information on the recently proposed US Educational Seismology Network (USESN) to share. As Sean suggests, those at the AGU meeting can meet at the top of the escalators at 6 PM and share a taxi. Confirmed so far are: John Lahr Karl Cunningham John Taber Steve Hammond If you're going to be at the meeting or live anywhere nearby, you won't want to miss this! Please post your intentions so we will know how large a table is required. Cheers, John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How do I upload my files?? From: "Larry Cochrane" cochrane@.............. Date: Fri, 8 Dec 2000 01:14:35 -0800 Bryan, Nice recording of the event. Event files are uploaded to my system using an email message. Attach one to four event files to a message and send it to event@............... Before you send in your files we need to come up with a unique station / sensor ID. This is the file extensions of your event files. I check and *.bg1 through 9, *.bgn, *.bge and *.bgz are free. If you would like to use another ID let me know so I can check that it is not being used by another station. -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: Bryan & Regina Goss To: Larry Cochrane Cc: psn-l@.............. Sent: Thursday, December 07, 2000 5:23 PM Subject: How do I upload my files?? I would like to upload EVANSVILLE,INDIANA . I got strong reading I am 216 miles away how do I do this and one more question How do I know where to Put the P and S markers? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Cache Updates on Web Cam's From: Arie Verveer ajbv@............ Date: Sat, 09 Dec 2000 14:58:00 +0800 Hi, While using Netscape, and a particular server, I found it rather frustrating that the images from a volcano Cam's wouldn't update. Tried, modifying the cache setting but with no success. A friend of mine, told me of this trick while using Netscape. Hold down the "Shift" key and with the "mouse" click the "Reload" button. It sends an instruction down to the server to get a fresh image. This might be useful if you are using Netscape. I believe this will not work with Explorer.? Volcano Cam's: http://educeth.ethz.ch/stromboli/livecams/index-e.html Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New kid on the PSN block. From: Mark Andrews mja6042@............. Date: Sun, 10 Dec 2000 15:37:53 -0600 Greetings Everyone, I would like to take this opportunity to introduce myself to the PSN. I have been lurking on the list serv for about six months now. As I am nearing the completion of my first seismometer I thought it would be a good time to make myself known and ask for some wisdom from the more experienced members. First a little about me: My name is Mark Andrews, I am 20 years old and I am from Austin, Texas. I am currently attending Texas A&M University, working on my undergraduate degree, a B.S. in Geology. I am an avid mineral collector and in my spare time I enjoy building things and learning how things work. My idea of the perfect job is getting paid to look at rocks under a microscope all day. As it is now I am a student worker for the technician that operates the four-spectrometer Cameca SX50 Electron Microprobe at Texas A&M. Now for my seismometer: At the beginning of last summer vacation I set out to build a seismometer. After doing a fair amount of reading and searching on the web I came across Larry Cochrane's site. I decided to build a Shackleford-Gundersen seismometer. It has taken a little longer than I had hoped because I had to do a lot of searching for information and parts. By the end of the summer I had the seismometer built and an amplifier/filter board wire wrapped. I was intending to make my own computer interface/A-D board but school got in the way. Instead, I'll be going with Larry Cochrane's A-D board which should work great. (Thanks Larry!) I should have everything online by the end of my Christmas break. I'm going to set the seismometer up in my dad's basement. My question, since I only have one sensor, is which way should I point the sensitive axis? (The sensor being in Austin, Texas) Texas isn't exactly known for its massive earthquakes. I was thinking about orienting it along a line that passed between Japan and the Aleutian Islands. I realize most people go with strictly North-South or East-West but at the start I'd just like to be able to detect a few nice quakes. I guess if I went with North-South I could catch seismic activity coming up from Mexico and South America which is a little closer anyway. What are everyone else's thoughts? Thanks for your time, Mark Andrews Aggie Class of '02 mja6042@............. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New kid on the PSN block. From: sean@........... Date: Sun, 10 Dec 2000 16:08:57 -0600 (CST) Mark, A horizontal seis is sensitive the the predominantly transverse waves propagating from the source. So if you want Japan/western Pacific data, orient it N-S. It will still pick up S. America events, but not as well. In the network I operated in the Aleutians, every station had a vertical and only an E-W horizontal, since most of the quakes were in the top of the subduction zone to the south of the backark island chain. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Helicorder updates on a web site From: The Lahrs johnjan@........ Date: Sun, 10 Dec 2000 15:49:06 -0700 I've worked out a way that someone running an Internet-connected PC with a continuously updating helicorder display could periodically put a copy of the computer screen on a web site. Alan Jones' AmaSeis data acquisition program keeps a helicorder display on the screen, and other programs probably do as well. I found a free program named SnapShot that one can set up to create a BMP image of the screen every hour (or other interval of your choice). I also found a free program, BMP2GIF that can run in a DOS Batch file and convert the file to GIF format. All that is left is to ftp the file to a web site from within the same batch file. The batch file would be scheduled to run a few minutes after each screen capture. I don't have AmaSeis running now, so can't try this out. If anyone else want to, I can post the two programs mentioned. Cheers, John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: The Lahrs johnjan@........ Date: Sun, 10 Dec 2000 15:56:43 -0700 I should have added that for this to work the PC's screen must be set to 8 bit (256 colors) -- at least I couldn't find any way around this. I tried using a BMP2JPG program, but even though JPG is not limited to 8 bit color the programs was! John * John C. and Jan H. Lahr *JohnJan@........ * 1925 Foothills Road * Golden, Colorado 80401-1718 * (303) 215-9913 * http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: macsmith macsmith@......... Date: Sun, 10 Dec 2000 13:47:32 -1000 Hi, I'm not sure if you are asking what lines should be in your batch file to ftp it. If you are, then, under windows nt: in your batch file add the line ftp -s: the file should have: open binary cd put quit I do this on a 24 hour basis with my graphs ( see http://www.macsmith.net/latestq.htm ). I use the nt scheduler for this, but it can only do this once per entry, ie to do it every 5 mins would need 288 entries. If you find another free scheduler, let me know. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meet me in SFO@Tommy's Joynt From: Bob Fryer bfryer@............ Date: Sun, 10 Dec 2000 16:29:44 -0800 Hi John and gang, Next weekend, a crew from the internet-tv company www.now.com will be in San Francisco because of the AGU meetings. They carry many earthquake related items on their website. Would it be appropriate to invite them to the PSN gathering? Take care, Bob Fryer http://www.now.com/ > OK, let's do it!!! > > Tommy's Joynt at the corner of Geary and Van Ness. > ><http://www.sfgate.co >m/eguide/barguide/neighborhood4.shtml> > on Saturday night, December 16, 6:30 PM. This restaurant has > good food at a reasonable price and is not so crowded that we would > have problems finding a table or two. I'll bring some information > on the recently proposed US Educational Seismology Network > (USESN) to share. > > As Sean suggests, those at the AGU meeting can meet at the top of > the escalators at 6 PM and share a taxi. ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.earthquakewarning.org --- __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: The Lahrs johnjan@........ Date: Sun, 10 Dec 2000 18:32:14 -0700 Thanks for the ftp lines, as it's good to have these things documented for other users. Each morning on my USGS Sun computer a cron program runs that extracts a few long period waveforms for the largest event to occur in the past 7 days. A few minutes later a scheduled task on the lobby display Win95 PC runs a batch file that downloads these files so that they will be displayed by Seismic Waves during the daytime. I'm not sure about WinNT, but on Win95 one can schedule multiple tasks with one entry in the scheduler. Within the Scheduled Tasks program, look at the properties of a specific task, click on the Schedule tab, press the Advanced button and then fill in the repeat interval in the Repeat Task section. Do you have to use "AT" commands on an NT? I like the seismograms on your web page. How do you create the GIF files? Cheers, John At 04:47 PM 12/10/00 , you wrote: >Hi, > >I'm not sure if you are asking what lines should be in your batch file to >ftp it. If you are, then, under windows nt: ... * John C. and Jan H. Lahr *JohnJan@........ * 1925 Foothills Road * Golden, Colorado 80401-1718 * (303) 215-9913 * http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: Arie Verveer ajbv@............ Date: Mon, 11 Dec 2000 10:07:12 +0800 Hi, If you are using a computer networked to Larry's "SDR" software then here is a free Helicorder program. The program also allows for digital filtering and the documentation also explains how to send the program's "gif" output to an ftp site. http://www.iinet.net.au/~ajbv/Software/Software.html Examples of output: http://www.iinet.net.au/~ajbv/ftp/Drum.html Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: The Lahrs johnjan@........ Date: Sun, 10 Dec 2000 20:01:21 -0700 Arie, I wonder how difficult it would be to interface your drum program to files in a different format? AmaSeis saves all of the data in one-hour- long files. I'm not sure what the format is. John At 07:07 PM 12/10/00 , you wrote: >Hi, If you are using a computer networked to Larry's "SDR" software then >here is a free Helicorder program. The program also allows for digital >filtering and the documentation also explains how to send the program's >"gif" output to an ftp site. * John C. and Jan H. Lahr *JohnJan@........ * 1925 Foothills Road * Golden, Colorado 80401-1718 * (303) 215-9913 * http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: Arie Verveer ajbv@............ Date: Mon, 11 Dec 2000 11:23:29 +0800 Hi, Not a problem, If you have some format details and a few example files, I'll see what can be done. Cheers and a merry Ho Ho Ho.. Arie The Lahrs wrote: > > I wonder how difficult it would be to interface your drum program to > files in a different format? AmaSeis saves all of the data in one-hour- > long files. I'm not sure what the format is. > John > At 07:07 PM 12/10/00 , you wrote: > >Hi, If you are using a computer networked to Larry's "SDR" software then > >here is a free Helicorder program. The program also allows for digital > >filtering and the documentation also explains how to send the program's > >"gif" output to an ftp site. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder updates on a web site From: macsmith macsmith@......... Date: Sun, 10 Dec 2000 17:26:40 -1000 Hi, I'm using winAt which is really a gui sitting on top of AT. It allows you to repeat a command every [date]. I interpret this as meaning what days, ie once per day max. Perhaps I need to read it again... The graphs are generated on my linux system using a free package called pgplot. Yesterday my X server went screwy so had to reboot part way through the day. Normally there is a full 24 hour plot on the web site. I'll have to check out your web site too... cheers macsmith __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: monitoring a remote seismograph From: Bob rwspahn@............. Date: Sun, 10 Dec 2000 22:07:31 -0600 Can anyone tell me how you go about monitoring a remote seismograph site? It will have AC power, the computer will be on site, and the link will have to be RF, (no phone lines). I have an ideal site for my seismometer, but will have to link it via amateur radio. It is at a repeater site and I have available, ATV (amateur television) and FM audio channels. I was thinking of using standard modems with the audio on the subcarrier, full duplex. Will Larry's program support remote data transfer? This does not have to be real time monitoring. What I intend to do, is poll the site and collect the information periodically. Any ideas ? Thanks, Bob - WD5BJW __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Helicorder view From: "Ted Blank" ted@.......... Date: Mon, 11 Dec 2000 09:09:04 -0500 The EMON program has an option, DisplayLines, which controls how many lines of history are displayed on the screen. The default is 1 for a single trace. However you can set higher numbers like 7 or 9 and the lines will display in helicorder-like mode. Wrap is from bottom to top. This is very handy when you want to do a "pedokinematic calibration" and need some time to dash to the recorder to see what happened. Regards, Ted Blank __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meet me in SFO@Tommy's Joynt From: Steve Hammond Shammon1@............. Date: Mon, 11 Dec 2000 10:35:05 -0800 Hi John, I'll be able to make the dinner see you at 6:00 and I would like to meet the folks from www.now.com. Regards, Steve Bob Fryer wrote: > > Hi John and gang, > > Next weekend, a crew from the internet-tv company www.now.com will be in > San Francisco because of the AGU meetings. They carry many earthquake > related items on their website. > > Would it be appropriate to invite them to the PSN gathering? > > Take care, > Bob Fryer > > http://www.now.com/ > > > OK, let's do it!!! > > > > Tommy's Joynt at the corner of Geary and Van Ness. > > > ><http://www.sfgate.co > >m/eguide/barguide/neighborhood4.shtml> > > on Saturday night, December 16, 6:30 PM. This restaurant has > > good food at a reasonable price and is not so crowded that we would > > have problems finding a table or two. I'll bring some information > > on the recently proposed US Educational Seismology Network > > (USESN) to share. > > > > As Sean suggests, those at the AGU meeting can meet at the top of > > the escalators at 6 PM and share a taxi. > > ----- earthquake WARNING research ----- > --- animals, people, scientific evidence --- > --- http://www.earthquakewarning.org --- > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Dead Sea Seismic Event From: GeE777@....... Date: Mon, 11 Dec 2000 16:45:34 EST Hello all; I am looking for any records of a seismic event in the Dead Sea area of about 4.7 magnitude occurring in October or early November, 1999. Can you direct me to a site where I can find this information? Regards. George Erich Geophysical Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Dead Sea Seismic Event From: "I.ES.N." info@........ Date: Mon, 11 Dec 2000 23:13:12 +0100 If I remember wright, it was an artificial experiment. Look at USGS web site or Orfeus. During that time I recived many e-mail about it and we recorded the maior event. Sorry, but I lost all..... Francesco. PSN Itlay __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Dead Sea Seismic Event From: "Ian Greenwood" judgedred@.............. Date: Mon, 11 Dec 2000 23:12:44 -0000 This may help http://www.emsc-csem.org/Html/JSOP_shot.html Explosion readings on 8th, 9th and 11th November 1999. Ian Subject: Dead Sea Seismic Event > Hello all; > > I am looking for any records of a seismic event in the Dead Sea area of about > 4.7 magnitude occurring in October or early November, 1999. Can you direct > me to a site where I can find this information? > > Regards. > > George Erich __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Message from James Lehman From: The Lahrs johnjan@........ Date: Mon, 11 Dec 2000 21:14:03 -0700 I will not be going to the SSA PSN meeting this year, so thought
I should post the message from James Lehman (see below) so that
those who do would be sure to invite him.

Larry, could you post on your PSN web site the date and time for
the PSN meeting this Saturday - in case others who are not on
the Email list would like to attend?

Location: Tommy's Joynt at the corner of Geary and Van Ness.
<http://www.sf gate.com/eguide/barguide/neighborhood4.shtml>

Time: Saturday night, December 16, 6:30 PM. 

Those at the AGU meeting can meet at the top of
the Moscone Center escalators at 6 PM and share a taxi.

Confirmed so far are:
John Lahr
Karl Cunningham
John Taber
Steve Hammond
Larry Cochrane
Bob Fryer
Crew from the internet-TV company www.now.com

If you're going to be at the meeting or live anywhere nearby, you
won't want to miss this!  Please post your intentions so we will know
how large a table is required.

From: "Lehman, James Dwight" <lehmanjd@.......>
Date: Mon, 11 Dec 2000 16:04:23 -0500
To: john@........
Subject: thank you
Priority: HIGH
X-Mailer: Execmail for Win32 Version 5.0.1 Build (55)


  John--Thank you for your note of last week in
reference to upcoming PSN meetings.  The Dec. 16
get-together is definitely not possible here, but a
gathering at Seis. Soc. meeting in April is a good
possibility.  I would like to see what all is cooking
these days with the western PSN folks.  I peruse the PSN
Web sites from time to time, and gather there are
several designs in use.  The AS-1 design looks sort of
neat for a vertical instrument.  We built a vertical
1-sec unit here out of componets from a typical hardware
store--l sec period/magnetic damping--at present it is
in use at Moravian College, Pennsylvania.
--  As April approaches, and a time & place is
determined for a meeting, I would be pleased to be
informed.  I will periodically check the PSN Websites.
Lehman, James Dwight
lehmanjd@.......              Jim Lehman
                     & nbsp;       SEASON'S GREETINGS--

* John C. and Jan H. Lahr                
*JohnJan@........                 &nb sp;   
* 1925 Foothills Road                    
* Golden, Colorado 80401-1718            
* (303) 215-9913                     ;     
* http://lahr.org/john-jan        & nbsp;      
Subject: Re: monitoring a remote seismograph From: "Larry Cochrane" cochrane@.............. Date: Mon, 11 Dec 2000 22:48:57 -0800 > Will Larry's program support remote data transfer? Bob, Not directly. What you can do is run two systems and network your SDR system, running in the DOS only mode of Win95/Win98, with another computer running Windows. These way event files can be placed onto the Windows system so they can be accessed remotely. To access the Window system I would recommend a program called PCAnywhere. This program can be used to remotely access a Windows system using the Internet or a modem and phone line. Hope this helps. -Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New kid on the PSN block. From: johnc c cole johnccole1@........ Date: Wed, 13 Dec 2000 00:50:32 -0600 Mark+ If you want to see what we are doing in the Houston area you can go to http://www.freeweb.pdq.net/fxc/four.htm You can go from my location to Franks. Frank has some outstanding equipment and submits great events . He is dean of the astronomy department at Sam Houston University in Huntsville. He just completed their new astrological observatory. jc ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New kid on the PSN block. From: johnc c cole johnccole1@........ Date: Mon, 11 Dec 2000 23:35:20 -0600 Mark It will be great to have you on the PSN. I have three and sometimes four detectors running at all times . I prefer N/S . I have some E/W. As far as being in an area that is not known for seismic activity,forget it. Ninety nine %and more of the events will be no closer than 1000 miles. We use the horizontal pendulum detectors and consistently record events from everywhere. The average distance is about six or seven thousand miles. If the instrument that you have is built right and is set up properly, your location is of no importance. Many of the instruments on PSN that you see every day ,i built. Frank Cooper in Friendswood, Tx. . Don Wheeler in sterling ,La. use my detectors. Frank uses two of my detectors and Don has three on line . Check them out. I also use Larry Cochrans amp etc. We all look forward to you being on PSN . Good luck . John C Cole ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ebay seismom. From: BOB BARNS roybar@........ Date: Wed, 13 Dec 2000 15:52:02 -0500 Hi gang, There is a Kinemetrics SS-1 Ranger seis. on ebay, #1201849860. The auction ends 12/21 Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Upload and GIF question From: Steve Hammond Shammon1@............. Date: Wed, 13 Dec 2000 14:47:29 -0800 Hi Larry, I uploaded 5 evewnt files of the 3.3 3KM from my house last night but I don't see them in the current event directory on your web site. Did I do something incorrect? I just sent each file attached to a note to event@............... The other question I have has to do with GIF settings in Winquake save. I tried to save the files in GIF format and receive an error message saying the pixel value was unsupported when using the program defaults. Save works on my notebook running Win95 but not on a desktop using Microsoft ME. Any suggestions? Regards, Steve Hammond PSN Aptos, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Source From: offutt@............ Date: Wed, 13 Dec 2000 15:56:07 -0700 (MST) A few mos ago, someone posted to this list the ID of a hardware outlet with a very comprehensive inventory. Not sure, but perhaps the name was Masters? Could someone kindly furnish the URL or web address again? Thanks. warren __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hardware Source From: ChrisAtUpw@....... Date: Wed, 13 Dec 2000 18:15:22 EST In a message dated 13/12/00, offutt@............ writes: > A few mos ago, someone posted to this list the ID of a hardware outlet > with a very comprehensive inventory. Not sure, but perhaps the name > was Masters? Hi there Warren, I'm not sure, but I think the one that you probably mean is McMaster-Carr Supply Company @ http://www.mcmaster.com/ - I have some references of other suppliers. Hope that this helps, Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hardware Source From: offutt@............ Date: Wed, 13 Dec 2000 17:01:29 -0700 (MST) Thank you, Chris. You hit the nail on the head ... or the supplier ID bullseye. Much obliged! Regards, warren __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Upload and GIF question From: "Larry Cochrane" cochrane@.............. Date: Wed, 13 Dec 2000 16:22:39 -0800 Hi Steve, ----- Original Message ----- From: "Steve Hammond" To: Sent: Wednesday, December 13, 2000 2:47 PM Subject: Upload and GIF question > Hi Larry, > > I uploaded 5 evewnt files of the 3.3 3KM from my house last night but I > don't see them in the current event directory on your web site. Did I do > something incorrect? I just sent each file attached to a note to > event@............... Try sending them in again. Last night I was doing some work on the archive system to allow the new PSN Type 4 event files to be sent in. I just sent a test file to event@.............. and it worked for me. Send me email if it doesn't work for you. I'll look through the log files to see if I can find what the problem is. > > The other question I have has to do with GIF settings in WinQuake save. > I tried to save the files in GIF format and receive an error message > saying the pixel value was unsupported when using the program defaults. > Save works on my notebook running Win95 but not on a desktop using > Microsoft ME. Any suggestions? You probably have your desktop computer set to true color. The GIF library used by the current release of WinQuake does not support this video mode. The next release of WinQuake, (do any day now...) should correct this problem. -Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: monitoring a remote seismograph From: barry lotz gbl@....... Date: Wed, 13 Dec 2000 10:50:16 -0800 Larry et al I think pcanywhere has been mentioned before but I am not familiar with the system requirements. I was hopeing to use a 386 very low power single board computer running dos/sdr at the remote site. Will pcanywhere(newer available versions at stores) support older more basic systems (ie 386 w/o plug and play etc)??? Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: monitoring a remote seismograph From: "Larry Cochrane" cochrane@.............. Date: Wed, 13 Dec 2000 19:55:37 -0800 Barry, PCAnywhere runs on all Windows operating systems. There is also a DOS version that someone on the list try to use with SDR. Apparently the DOS TSR that PCAnywhere uses interfered with the 1 ms interrupt need for accurate time keeping. The TSR must be disabling interrupts for a long period of time so SDR looses time. -Larry Cochrane ----- Original Message ----- From: "barry lotz" To: Sent: Wednesday, December 13, 2000 10:50 AM Subject: Re: monitoring a remote seismograph > Larry et al > I think pcanywhere has been mentioned before but I am not familiar with the > system requirements. I was hopeing to use a 386 very low power single board > computer running dos/sdr at the remote site. Will pcanywhere(newer available > versions at stores) support older more basic systems (ie 386 w/o plug and play > etc)??? > Regards > Barry > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: another From: "Bryan & Regina Goss" bgoss@.................. Date: Wed, 13 Dec 2000 21:56:22 -0600 I have one Lehman Seismometer N/S using Larry,s electronics and plan = build another do you have a website or pictures I would like to see your = detectors.I have just got going in the last month here is my seismograph = just prior to completion = http://www.tsixroads.com/~spardue/seismograph/seismograph.htm I now have it in a plexa glass box this took some time to build but = seems to work very well at keeping out air currents and spiders which we = have lot,s of. I plan to update the pics this weekend.=20
I have one Lehman Seismometer N/S = using Larry,s=20 electronics and plan build another do you have a website or = pictures I=20 would like to see your detectors.I have just got going in the last month = here is=20 my seismograph just prior to completion ht= tp://www.tsixroads.com/~spardue/seismograph/seismograph.htm
I now have it in a plexa glass box this = took some=20 time to build but seems to work very well at keeping out air currents = and=20 spiders which we have lot,s of. I plan to update the pics this = weekend.
 
Subject: Sound? From: "Bryan & Regina Goss" bgoss@.................. Date: Wed, 13 Dec 2000 22:14:32 -0600 Just wandering if any one had tried to convert event files to some form = of audio and play it back at a higher speed through the sound card? = here is what I was able to do I saved a file from winquake in PSN Binary = to c:\whatever then I opened a program called cool edit 2000 "awesome sound editing = software" and opened it under the *.*all file option told it 44100 16-bit Intel PCM it opened the event but played it super = fast so I slowed it down but I still have problems it seems to cut off = part of the event above a certain db level any help would be = appreciated.
Just wandering if any one had tried to = convert=20 event files to some form of audio and play it back at a higher speed = through=20 the sound card? here is what I was = able to do I=20 saved a file from winquake in PSN Binary to c:\whatever
then I opened a program called cool = edit 2000=20 "awesome sound editing software" and opened it under the *.*all file=20 option
told it 44100 16-bit Intel PCM it = opened the event=20 but played it super fast so I slowed it down but I still have problems = it seems=20 to cut off part of the event above a certain db level any help would be=20 appreciated.
Subject: Sound and precursors From: Mariotti Mauro mariottim@............ Date: Thu, 14 Dec 2000 09:39:19 +0100 It's around two years that i looking for precursors on seismic signal speeded up by wave conversions. I use the SOX converter. It's able to convert binary files to waw in many ways and made also changes on loudness of the file as a volume control. It's a wonderful experiment, i planning to translate one my web page in english but due to the time i don't did so at moment. If you want to see the italian page you could visit this page: http://mariottim.interfree.it/mfonos.htm There an interesting correlation on precursors signal recorded in 8000 times speeded up seismic signals and ELF recorded by elfrad group. And other interesting things like the ability to recognize doppler effect on trucks passing near the station. At 22.14 2000-12-13 -0600, you wrote: > Just wandering if any one had tried to convert event files to some form >of audio and play it back at a higher speed through the sound card? here >is what I was able to do I saved a file from winquake in PSN Binary to >c:\whatever then I opened a program called cool edit 2000 "awesome sound >editing software" and opened it under the *.*all file option told it 44100 >16-bit Intel PCM it opened the event but played it super fast so I slowed >it down but I still have problems it seems to cut off part of the event >above a certain db level any help would be appreciated. Mauro Mariotti mariottim@............ http://mariottim.interfree.it __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Sound? From: Jim Hannon jmhannon@........ Date: Thu, 14 Dec 2000 06:10:52 -0600 I have done it with CoolEdit. Here is an example http://soli.inav.net/~jmhannon/950516a.au One problem with the method you described is that the header in the PSN event file is not always an even number of bytes. This causes Cool edit to read the data portion of the file misaligned with the 16 bit words of the data. I wrote a little program to strip off the header information which fixes that problem. You will notice a little clipping in my example above but that is due to the original data being clipped. At 10:14 PM 12/13/00 -0600, you wrote: >Just wandering if any one had tried to convert event files to some form of >audio and play it back at a higher speed through the sound card? here is >what I was able to do I saved a file from winquake in PSN Binary to c:\whatever >then I opened a program called cool edit 2000 "awesome sound editing >software" and opened it under the *.*all file option >told it 44100 16-bit Intel PCM it opened the event but played it super >fast so I slowed it down but I still have problems it seems to cut off >part of the event above a certain db level any help would be appreciated. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Sound? From: "Bryan Goss" bgoss@....................... Date: Thu, 14 Dec 2000 10:56:56 -0600 ---------- Original Message ---------------------------------- From: Jim Hannon Reply-To: psn-l@.............. Date: Thu, 14 Dec 2000 06:10:52 -0600 >I have done it with CoolEdit. Here is an example >http://soli.inav.net/~jmhannon/950516a.au One problem with the method you >described is that the header in the PSN event file is not always an even >number of bytes. This causes Cool edit to read the data portion of the file >misaligned with the 16 bit words of the data. I wrote a little program to >strip off the header information which fixes that problem. You will notice >a little clipping in my example above but that is due to the original data >being clipped. > >At 10:14 PM 12/13/00 -0600, you wrote: >>Just wandering if any one had tried to convert event files to some form of >>audio and play it back at a higher speed through the sound card? here is >>what I was able to do I saved a file from winquake in PSN Binary to c:\whatever >>then I opened a program called cool edit 2000 "awesome sound editing >>software" and opened it under the *.*all file option >>told it 44100 16-bit Intel PCM it opened the event but played it super >>fast so I slowed it down but I still have problems it seems to cut off >>part of the event above a certain db level any help would be appreciated. > >Jim Hannon >http://soli.inav.net/~jmhannon/ >42,11.90N,91,39.26W >WB0TXL > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > Can you send me a copy or link to your software? by the way nice web page!! Thanks Bryan S Goss __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismometer Basic Frame Construction Thought From: "meredith lamb" mlamb1@.......... Date: Fri, 15 Dec 2000 11:52:56 -0800 Hi all, We've all seen alot of the same general "swinging gate" seismometers construction method....i.e., the major pieces being the flat base plate and a mast attached to it. I suppose thats all well and good....if.....the amateur builder is lucky enough to obtain thick enough, or enough reinforcement additions to make it stable, to avoid alot of operation adjustments. This is a definite challenge to do. I've made a number of Shackleford-Gunderson seismos that more or less use a "box" frame aspect that are a different approach obviously. Admittedly with using steel and aluminum, they do take a month or more to mechanically settle down or stabilize themselves, for a more consistent operation thereafter. The main thought I bring here, is nothing more than intertaining the though of using the same approach for the more typical "swinging gate" seismometer and its base "frame" variation. For example: "If" one has a box (of whatever material), it would be likely to be more structurally stronger than the typical flat base plate and mast usually utilized by amateurs. The key here is obviously finding the strongest material again.....but....it could open alittle more options for amateur builders. With such a frame, it would be much easier to add support braces if needed. Naturally, the seismo boom/mast/mass and sensor method would have to be configured for use within such a frame. Its also possible to envision such a "frame" or "box", being possible with only 4 sides being utilized, without the top and bottom....or....the complete "box" of 6 sides, but this is dependent on the strength of the material joints, thickness. Naturally one side would have to allow access. Going further....."if" I were deprived of say, thick aluminum or other metals material, or cost limitations/budget; and the desire is there....I would "go for" whatever material I could afford....even it was a thick WOOD frame approach. Of course, I'd use a sealer/paint to give some more stability or freedom from moisture absorption. Perhaps the only other positive aspect of this approach, could be the simple addition of insulation on the inside and outside for additional thermal variation protection. This idea is not original, I'am sure, but I've yet to see any seismometer using this...outside of a "SG" type design. Perhaps others might have other limiting application objections...or have even tried this??? Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismometer Basic Frame Construction Thought From: "Raul J. Alvarez" ralvarez@........ Date: Fri, 15 Dec 2000 12:18:39 -0700 Just wanted to add my 2 cents (actually 1.1 cent after taxes) to Meredith's ideas. On the concept of using a "box" of thinner aluminum, why not use two sheets of thin aluminum with a "honeycomb" structure in between the plates? Sort of the methods that were used in the early space capsules. Could be held together with epoxy. Well, there it is - 2 cents worth! 8>) Hoilday best to all. Raul Alvarez __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seis box for horizontal From: sean@........... Date: Fri, 15 Dec 2000 14:27:20 -0600 (CST) Meredith, Considering a box frame for a horizontal seis is certainly a good idea. In fact, the frame for the famous Sprengnether long period horizontal as used in the WWNSS, is such a design if you look at it properly. The layout is that of a large cubic box cut in half diagonally through opposite vertical corners. Then the remaining two sides are cut at an angle from near the top of the remaining top corner to near the base. Thus the remaining corner is the support mast, with the diagonal cut across the base being the front of the horizontal seismometer. For the Sprengnether seis, two large aluminum castings make up this construction, one for the base, and another for the support mast with the diagonal braces. The boom, mass, magnets, etc are mounted inside. The taught wire supports are fastened to the top front and base rear of the upright (with the end of the boom forking to bypass it). There is a drawing of it on my web site. http://www.eas.slu.edu/People/STMorrissey/index.html stmmisc.html" PSN INFO ... SLU Seismic Network (abstracts.html" Abstract of paper for 2000 AGU meeting: has been updated) Finding the ideal cubic box made of thick wall aluminum or stainless steel could be a problem. I would think that 16" on a side would be a minimum, making the front diagonal 22.6", and a consideration for the size of the pier. However, a two piece construction of a thick triangular base and a bolted on corner angle would work. The corner could be made with a piece of 1/8" aluminum sheet bent in the middle after cutting the diagonal sides, and joined to the base with T or J bolts. Someone with a Tig/Mig welder could make it a one-piece design. Bending the angle to less than 90 degrees would allow for a narrower profile. I think that the massive side angle braces would allow 1/8" aluminum to be used for the base if a heavy beam (like 2"w x 1/2" thick Al bar) was run across the front between the lower front of the side angles (where the leveling screws would be installed. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Popocatepetl From: Mark Robinson other@............... Date: Sat, 16 Dec 2000 23:28:27 +1300 "Authorities in Mexico have declared a state of emergency and are preparing to evacuate 15,000 people living in the vicinity of Popocatepetl, a volcano 60km (37 miles) east of Mexico City." http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl From: Arie Verveer ajbv@............ Date: Sat, 16 Dec 2000 20:17:22 +0800 Hi, Popo live cam at http://www.cenapred.unam.mx/popo/imagen.html I'm just watching the early dawn right now! Arie > "Authorities in Mexico have declared a state of emergency and are > preparing to evacuate 15,000 people living in the vicinity of > Popocatepetl, a volcano 60km (37 miles) east of Mexico City." > > http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm > > Mark > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Popocatepetl From: "Kareem" kareemjupiter@............. Date: Sat, 16 Dec 2000 09:39:38 -0800 Several weeks ago someone posted a email with a link to a website containing a dozen or so live views/cams of volcanoes. Does anyone have a copy of that email. -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Arie Verveer Sent: Saturday, December 16, 2000 4:17 AM To: psn-l@.............. Subject: Re: Popocatepetl Hi, Popo live cam at http://www.cenapred.unam.mx/popo/imagen.html I'm just watching the early dawn right now! Arie > "Authorities in Mexico have declared a state of emergency and are > preparing to evacuate 15,000 people living in the vicinity of > Popocatepetl, a volcano 60km (37 miles) east of Mexico City." > > http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm > > Mark > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl From: barry lotz gbl@....... Date: Sat, 16 Dec 2000 01:50:56 -0800 Kareem You might try http://www.dartmouth.edu/~volcano/ Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl From: Seisguy@....... Date: Sat, 16 Dec 2000 13:33:35 EST Crowds Flee Spewing Mexico Volcano By JULIE WATSON ..c The Associated Press MEXICO CITY (AP) - Calling it a pressure cooker with a rattling lid, officials kept a wary eye on a towering volcano Saturday and ordered thousands evacuated as the fiery crater spat out gas, vapor and ash for a fifth straight day. Although there were fewer eruptions Friday and Saturday, experts feared the Popocatepetl Volcano could begin spewing lava. Intense, unprecedented seismic activity inside the volcano indicated that magma may be moving within, said scientist Roberto Quass of the National Center for Disaster Prevention. Many in towns near the crater have felt a series of small earthquakes. ``We have a pressure cooker, and the valve is beginning to shake,'' volcano expert Carlos Valdez said. The volcano, located 40 miles southeast of Mexico City, overlooks the sprawling capital. Residents in the volcano's shadow have been walking the streets with medical masks over their mouths to avoid inhaling the ash. On Friday, authorities ordered the evacuation of 14,000 people in 11 communities within eight miles of the crater. Smoke billowed from Popocatepetl's mouth as more than 300 buses arrived to take people from its slopes to government shelters a safe distance away. But despite the glowing crater, many residents did not want to leave. It has been 800 years since Popocatepetl's last catastrophic eruption, and many were skeptical of official warnings. The last time officials ordered an evacuation was six years ago, when the volcano started erupting after lying largely dormant since 1927. ``I'm rethinking leaving because we don't have much, but the little that we do have, they'll probably rob,'' said Rodrigo Sevilla, 40, as soldiers nearby helped load people onto buses to leave his town, Xalitzintla. The 17,886-foot volcano has been shooting out vapor, ash and rock intermittently since December 1994, but the activity has been especially intense of late. On Tuesday, it erupted 200 times, a record number for a single day. On Thursday, it threw ash over a 50-mile radius and spat incandescent fragments that rolled down its slopes. Airlines canceled up to 30 flights into the Mexico City airport for a second straight day amid fears the ash could interfere with their engines. Most flights, though, went ahead as scheduled. AP-NY-12-16-00 1029EST __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Volcano photos From: ChrisAtUpw@....... Date: Sat, 16 Dec 2000 20:36:43 EST In a message dated 16/12/00, kareemjupiter@............. writes: > Several weeks ago someone posted a email with a link to a website containing > a dozen or so live views/cams of volcanoes. Kareem, Also have a look at http://educeth.ethz.ch/stromboli/livecams/index-e.html --- a lot of the hyper links in http://www.dartmouth.edu/~volcano/ appear to be broken. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Volcano photos From: "Kareem" kareemjupiter@............. Date: Sun, 17 Dec 2000 00:08:04 -0800 Close - That's the URL that I was looking for. Thanks to all of you who replied. Kareem -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Saturday, December 16, 2000 5:37 PM To: psn-l@.............. Subject: Re: Volcano photos In a message dated 16/12/00, kareemjupiter@............. writes: > Several weeks ago someone posted a email with a link to a website containing > a dozen or so live views/cams of volcanoes. Kareem, Also have a look at http://educeth.ethz.ch/stromboli/livecams/index-e.html --- a lot of the hyper links in http://www.dartmouth.edu/~volcano/ appear to be broken. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl NOW ! From: Mark Robinson other@............... Date: Mon, 18 Dec 2000 02:08:25 +1300 Arie Verveer wrote: > > Hi, Popo live cam at http://www.cenapred.unam.mx/popo/imagen.html > > I'm just watching the early dawn right now! > > Arie > > > "Authorities in Mexico have declared a state of emergency and are > > preparing to evacuate 15,000 people living in the vicinity of > > Popocatepetl, a volcano 60km (37 miles) east of Mexico City." > > > > http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm > > > > Mark > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: cheaper magnets! From: heweisss@................ Date: Mon, 18 Dec 2000 14:51:02 +0800 Gentlemen: Cadee Magnets Complex Chongqing(CMCC) is the professional manufacturer of NdFeB,AlNiCo,Ferrite(Ba or Sr) permanent magnets located in China mainland. We accuminlated almost 30 years of experience and currently export our products to clients in Europe,North American,Southeast Asia,and Hongkong through importers located there. Maybe you have already been our client for a long time. To serve our clients better, we began our effort to get them closer. As a part of our effort,we send this E-mail and hope it to be the begining of profitable business relation. We provide full set of our techdata in email on your demand. We will be glad to get customized requirement or inquiry on te chnical details of our products . We are quite sure of your more profit to do business with us! Sincerely Yours hewei Chief of trade division CMCC. fax: +86 23 62812123 voice: +86 23 62820911 email: heweisss@................ address: 1F-4 No.59 xiangsui Road Nanpin Chongqing China. 400060 Subject: From: "Bryan Goss" bgoss@....................... Date: Tue, 19 Dec 2000 11:42:42 -0600 Could someone send me link to live cam of volcano in Mexico. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Volcano cam From: Mike Lozano mikel@............... Date: Tue, 19 Dec 2000 11:50:00 -0600 Bryan, I've got it on my web page at: http://www.sciencearea.com/latest.htm Mike Bryan Goss wrote: > Could someone send me link to live cam of volcano in Mexico. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: From: "Ian Greenwood" judgedred@.............. Date: Tue, 19 Dec 2000 19:03:10 -0000 Try these: - http://www.cenapred.unam.mx/popo/UltimaImagenVolcan2.html of http://www.dartmouth.edu/~volcano/ http://www.cenapred.unam.mx/popo/imagen.html > Could someone send me link to live cam of volcano in Mexico. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl NOW ! From: Bob Smith bobsmith5@........ Date: Thu, 21 Dec 2000 16:37:44 -0500 The live-cam links appear to be now broken????? Bob Smith Mark Robinson wrote: > > Arie Verveer wrote: > > > > Hi, Popo live cam at http://www.cenapred.unam.mx/popo/imagen.html > > > > I'm just watching the early dawn right now! > > > > Arie > > > > > "Authorities in Mexico have declared a state of emergency and are > > > preparing to evacuate 15,000 people living in the vicinity of > > > Popocatepetl, a volcano 60km (37 miles) east of Mexico City." > > > > > > http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm > > > > > > Mark > > > > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Popocatepetl NOW ! From: "Raul J. Alvarez" ralvarez@........ Date: Thu, 21 Dec 2000 16:57:32 -0700 Bob and all, For the past two days, I have been receiving pix that have corrupted data. Since the web link is still good, but the pix is missing, I assume the camera or the microwave link has gone down. Raul Alvarez Bob Smith wrote: > The live-cam links appear to be now broken????? > > Bob Smith > > Mark Robinson wrote: > > > > Arie Verveer wrote: > > > > > > Hi, Popo live cam at http://www.cenapred.unam.mx/popo/imagen.html > > > > > > I'm just watching the early dawn right now! > > > > > > Arie > > > > > > > "Authorities in Mexico have declared a state of emergency and are > > > > preparing to evacuate 15,000 people living in the vicinity of > > > > Popocatepetl, a volcano 60km (37 miles) east of Mexico City." > > > > > > > > http://news.bbc.co.uk/hi/english/world/americas/newsid_1073000/1073155.stm > > > > > > > > Mark > > > > > > > __________________________________________________________ > > > > > > Public Seismic Network Mailing List (PSN-L) > > > > > > To leave this list email PSN-L-REQUEST@.............. with > > > the body of the message (first line only): unsubscribe > > > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > > -- > > --------- Avoid computer viruses -- Practice safe hex > ------------- > * * Specializing in small, cost effective embedded control > systems * * > Robert L. (Bob) Smith Smith Machine Works, Inc. > internet bobsmith5@........ 9900 Lumlay Road > landline 804/745-1065 Richmond, Virginia > 23236+1004 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Amplifier noise? From: Mark Andrews mja6042@............. Date: Fri, 22 Dec 2000 20:53:50 -0600 Hello Everyone, Recently I finished construction on my first seismometer. I used schematics off of Larry Cochrane's web site to wire wrap the amplifier: http://psn.quake.net/sgsumamp.gif and http://psn.quake.net/sgproc.gif I housed the amplifier in a steel box, grounded to analog ground on the amplifier board. I have the output of the amplifier connected to Larry's 16 bit A to D board with about 16 feet of shielded wire. The shield, around the wire, is grounded to the case of my computer. When viewing the output with SDR I am getting about 80 to 100 counts of continuous noise. I don't know what the frequency of the noise is but the period is too short to see on SDR. Is this noise level abnormally high and does anyone have any suggestions on how to reduce the noise. Thanks for your time! Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: two sites on the web From: angel rodriguez angel@............ Date: Sat, 23 Dec 2000 08:32:39 -0500 Merry Christmas to everyone! Lars Ottemoeller a Norwegian friend sent me these two URL that might be of interest to seismograph builders. http://micromachine.stanford.edu/smssl/projects/Geophones/ the article called School Yard Seismology in http://orfeus.knmi.nl/newsletter/vol2no3/ Lars is the one who wrote the program to convert PSN format to SEISAN format. Angel angel@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Amplifier noise? From: Jim Hannon jmhannon@........ Date: Sat, 23 Dec 2000 08:05:37 -0600 Mark, I think that what you are seeing is about the noise level of Larry,s 16 bit A/D card. You can check this by operating the A/D card with it's input shorted. Check the noise level and see how it compares to the noise when your amplifier is connected. At 08:53 PM 12/22/00 -0600, you wrote: >Hello Everyone, > > >Recently I finished construction on my first seismometer. I used >schematics off of Larry Cochrane's web site to wire wrap the amplifier: >http://psn.quake.net/sgsumamp.gif and http://psn.quake.net/sgproc.gif > >I housed the amplifier in a steel box, grounded to analog ground on the >amplifier board. > >I have the output of the amplifier connected to Larry's 16 bit A to D board >with about 16 feet of shielded wire. The shield, around the wire, is >grounded to the case of my computer. When viewing the output with SDR I am >getting about 80 to 100 counts of continuous noise. I don't know what the >frequency of the noise is but the period is too short to see on SDR. > >Is this noise level abnormally high and does anyone have any suggestions on >how to reduce the noise. > >Thanks for your time! > >Mark > > Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Thanks for the great sites! From: Mike Lozano mikel@............... Date: Sat, 23 Dec 2000 08:51:03 -0600 Angel, Fantastic sites you recommended! Merry Christmas to everyone on the list! Mikel, K5RLY http://www.sciencearea.com Austin, TX angel rodriguez wrote: > Merry Christmas to everyone! > > Lars Ottemoeller a Norwegian friend sent me these two URL that might > be of interest to seismograph builders. > > http://micromachine.stanford.edu/smssl/projects/Geophones/ > > the article called School Yard Seismology in > http://orfeus.knmi.nl/newsletter/vol2no3/ > > Lars is the one who wrote the program to convert PSN format to SEISAN > format. > > Angel > > angel@............ > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Amplifier noise? From: Mark Robinson other@............... Date: Sun, 24 Dec 2000 10:55:04 +1300 Hi Mark, without referring to the specifics of Larry's amplifier or A-D I would suggest a small rearrangement of your earthing arrangement. In general it is good practise to keep all the sheilding and casework bonded together and kept insulated from the electronics at all but one point. This keeps all the metalwork electrically safe, reduces the possibility of any of it acting as an antenna, and stops any voltage gradient (read earth loop) present bewteen the computer and the amplifier or sensor from adding to the signal as an error. The main system earth is usually a low impedance balanced point in the middle of the power supply. regards Mark Mark Andrews wrote: > > Hello Everyone, > > Recently I finished construction on my first seismometer. I used > schematics off of Larry Cochrane's web site to wire wrap the amplifier: > http://psn.quake.net/sgsumamp.gif and http://psn.quake.net/sgproc.gif > > I housed the amplifier in a steel box, grounded to analog ground on the > amplifier board. > > I have the output of the amplifier connected to Larry's 16 bit A to D board > with about 16 feet of shielded wire. The shield, around the wire, is > grounded to the case of my computer. When viewing the output with SDR I am > getting about 80 to 100 counts of continuous noise. I don't know what the > frequency of the noise is but the period is too short to see on SDR. > > Is this noise level abnormally high and does anyone have any suggestions on > how to reduce the noise. > > Thanks for your time! > > Mark > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Amplifier noise? From: "Larry Cochrane" cochrane@.............. Date: Sat, 23 Dec 2000 16:51:54 -0800 Mark, Jim and Others... With the input shorted at the A/D board there should only be +- 4 or 5 counts of noise. Either Mark has a ground loop problem or his Amp is oscillating. -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: "Jim Hannon" To: Sent: Saturday, December 23, 2000 6:05 AM Subject: Re: Amplifier noise? > Mark, > I think that what you are seeing is about the noise level of Larry,s 16 > bit A/D card. You can check this by operating the A/D card with it's input > shorted. Check the noise level and see how it compares to the noise when > your amplifier is connected. > > At 08:53 PM 12/22/00 -0600, you wrote: > > > >Hello Everyone, > > > > > >Recently I finished construction on my first seismometer. I used > >schematics off of Larry Cochrane's web site to wire wrap the amplifier: > >http://psn.quake.net/sgsumamp.gif and http://psn.quake.net/sgproc.gif > > > >I housed the amplifier in a steel box, grounded to analog ground on the > >amplifier board. > > > >I have the output of the amplifier connected to Larry's 16 bit A to D board > >with about 16 feet of shielded wire. The shield, around the wire, is > >grounded to the case of my computer. When viewing the output with SDR I am > >getting about 80 to 100 counts of continuous noise. I don't know what the > >frequency of the noise is but the period is too short to see on SDR. > > > >Is this noise level abnormally high and does anyone have any suggestions on > >how to reduce the noise. > > > >Thanks for your time! > > > >Mark > > > > > > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Amplifier noise? From: ChrisAtUpw@....... Date: Sat, 23 Dec 2000 22:17:49 EST In a message dated 23/12/00, mja6042@............. writes: > When viewing the output with SDR I am getting about 80 to 100 counts of > continuous noise. I don't know what the frequency of the noise is but the > period is too short to see on SDR. > Is this noise level abnormally high and does anyone have any suggestions on > how to reduce the noise. Hi there Mark, This noise level is much greater than I would normally expect. Check your power supplies for noise with AC DVM. You aren't using the computer power supplies are you? They can be very noisy. Also check the earth connection. Do you have access to an oscilloscope? A quick look at the waveform, frequency, etc. can be very helpful. Check that you have the correct values of gain resistors in the feedback circuits. I have been sold resistors which are a factor of 10 out. Double check that you have made the circuits properly. Short the input to the ADC and check the noise level. Then check with the input to the first amplifier shorted, but everything else connected. If this doesn't cure it, you will need to short the input to the last OpAmp, check the level and work back chip by chip until you find the problem circuit. Look for mains / computer noise, oscillations, a dud OpAmp, dry solder joints, noisy resistors, faulty capacitors, etc. Hope that these suggeations are of some help, Chris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: =?iso-8859-1?Q?Popocat=E9petl?= - New material Image From: Arie Verveer ajbv@............ Date: Sun, 24 Dec 2000 13:44:51 +0800 Hi, The attached image is a pre and post image of the volcano Popocatépetl. It was crudely image processed to show the new material that the volcano ejected during its recent eruption. The dark line on the right side of picture is new material. I assume from the sunrise and set the camera is positioned north ot the volcano and thus the material was deposited mainly south ? Arie Subject: Re: =?iso-8859-1?Q?Popocat=E9petl?= - New material Image From: sean@........... Date: Sun, 24 Dec 2000 01:45:31 -0600 (CST) PLEASE DON'T ATTACH IMAGES TO PSN EMAIL. Many of us don't read mail with a browser. I read mail via a Unix server on a distributed system. If you want to point to an image, post the URL, and we can look it up sometime when we are connected to the web. Thanks, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: =?iso-8859-1?Q?Popocat=E9petl?= - New material Image From: sean@........... Date: Sun, 24 Dec 2000 01:45:31 -0600 (CST) PLEASE DON'T ATTACH IMAGES TO PSN EMAIL. Many of us don't read mail with a browser. I read mail via a Unix server on a distributed system. If you want to point to an image, post the URL, and we can look it up sometime when we are connected to the web. Thanks, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Amp Noise From: Mark Andrews mja6042@............. Date: Sun, 24 Dec 2000 04:10:03 -0600 Thanks everyone for your helpful suggestions. I've managed to cut back on the noise slightly and I'll continue with what you have suggested. Have a merry Christmas! Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 4.4ML at 34.6N 119.1w @ 01:42:20.2 UTC From: steve hammond shammon1@............. Date: Sun, 24 Dec 2000 00:28:32 -0800 Did anybody record this event? This is in the same area that the 1857 8.5 - 9.1ML Fort Tejon and the 1952 Tehacapi 7.4 events occurred. A search of the Berkley database yielded the following. This is the largest event in this area for some time. Date Time Lat Lon Depth Mag Magt Nst Gap Clo RMS SRC Event ID ------------------------------------------------------------------------ ---------------------- 1995/06/05 14:59:46.94 34.8870 -119.1990 9.67 3.20 l 106 0.32 CI 2000/12/24 01:04:20.99 34.9225 -119.0322 19.24 4.50 Mlt 22 80 6 0.21 NC 511041332 Regards, Steve Hammond PSN Aptos, California __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 4 pole neodymium magnet/s From: "meredith lamb" mlamb1@.......... Date: Sun, 24 Dec 2000 10:20:16 -0800 Hi all, Merry Christmas everyone. Curiosity thought. Anyone using 4 pole salvaged computer neo magnets with regular coils in a seismo? Somewhat akin to the Wondermagnet/Forcefield items....like: http://www.wondermagnet.com/dev/magnet42.html Even just using one magnet, with a coil moving laterally across the face seems to be just as good as using a large old alnico magnet with the coil between the poles in visual hand/meter tests. Two neo magnets mounted in the usual "U" iron frame fashion seems to be 2 to 4 times output better, than using just one. I think their is 4 fields between the magnets....but they don't seem to contradict the coil output at all. Two minor fields on each magnet, and the major attracting fields between the spaced magnets. I used old iron curtain rod brackets, mechanically coupled for the "U" frame. Each magnet is simply magnetically placed on each inside face of the brackets. This may lessen the overall magnetic field overall. I haven't tried any spaced but magnetically attracting and facing magnets, without, a iron frame but it could show a difference or change in result? The coil works best when centered down and between the magnets....unlike a usual alnico magnet where the coil is roughly 1/2 in the magnet opposing faces. I used a 2K "pancake" shaped coil. I do note some eddy current damping when the leads are shorted. Naturally a lower resistance coil would be better, or, 2-3 (2k) coils in parallel would be more effective. Think the subject has been covered before to some degree in the past emails...but I dread spending days going through all them past PSN emails files.....ha. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MERRY CHRISTMAS From: "Francesco" franuc@...... Date: Sun, 24 Dec 2000 19:20:49 +0100 MAY BE A CHRISTMAS OF HOPE, SERENITY AND PEACE. Sincerly yours: Francesco, Giovanni, Roberto, Mauro, Giacomo, Antonio, Paolo, Sandro, = Gaetano, Claudio and others members of=20 =20 PSN Italy - Italian Experimental Seismic Network.
MAY BE A = CHRISTMAS=20 OF  HOPE, SERENITY AND PEACE.
 
 
Sincerly=20 yours:
Francesco, = Giovanni,=20 Roberto, Mauro, Giacomo, Antonio, Paolo, Sandro, Gaetano, Claudio and = others=20 members of
 
PSN = Italy  - Italian=20 Experimental Seismic Network.
Subject: Re: 4.4ML at 34.6N 119.1w @ 01:42:20.2 UTC From: The Lahrs johnjan@........ Date: Sun, 24 Dec 2000 20:10:16 -0700 Hi Steve, I did a search at this NEIC site: http://neic.usgs.gov/neis/epic/epic_circ.html for events within 25 km of the recent one with magnitude of 4 or greater. You have to go back 19 years to 1981 to find a larger event, a mag 4.9. I wonder if this area's seismicity will pick up prior to another great event? It would be nice to be able to plot a map of the events that are found in such a search. Does anyone have a program designed to do this? In fact it would be best if it were part of a web site so that no local software was required. John E A R T H Q U A K E D A T A B A S E FILE CREATED: Sun Dec 24 19:59:26 2000 Circle Search Earthquakes= 10 Circle Center Point Latitude: 34.923N Longitude: 119.032W Radius: 25.000 km Catalog Used: PDE Magnitude Range: 4.0 - 10.0 Data Selection: Historical & Preliminary Data CAT YEAR MO DA O-TIME LAT LONG DEP MAG IEFM DTSVNWG DIST NFPO km TFS __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 4.4ML at 34.6N 119.1w @ 01:42:20.2 UTC From: Stephen & Kathy mortskm@....... Date: Sun, 24 Dec 2000 19:39:12 -0800 Yes, I did get a small recording on my Dataq system. It was about 290 miles from my station. It was about 0.378 volts peak to peak, out of a possible 20 volts. The noise level before the event was about 0.100 volts p to p. My noise level is normally around 0.050 volts p to p,, unless the surf is up,,, with an 18 ft surf between San Francisco and Eureka, my noise goes up to about 0.200 volts. MAP 4.4 2000/12/23 17:04:21 34.928N 119.023W 15.1 9 km ( 5 mi) W of Grapevine, CA Merry Christmas and a Happy Holiday to all, Stephen Mortensen Station #55 near Pilot Hill Ca 38.828N 120.979W steve hammond wrote: > Did anybody record this event? This is in the same area that the 1857 8.5 - > 9.1ML Fort Tejon and the 1952 Tehacapi 7.4 events occurred. A search of the > Berkley database yielded the following. This is the largest event in this > area for some time. > > Date Time Lat Lon Depth Mag Magt Nst Gap Clo > RMS SRC Event ID > ------------------------------------------------------------------------ > ---------------------- > 1995/06/05 14:59:46.94 34.8870 -119.1990 9.67 3.20 l 106 > 0.32 CI > 2000/12/24 01:04:20.99 34.9225 -119.0322 19.24 4.50 Mlt 22 80 6 > 0.21 NC 511041332 > > Regards, Steve Hammond > PSN Aptos, California __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Help From: "Tom Frey" tfreyis@........ Date: Mon, 25 Dec 2000 18:16:40 -0800 =20 Greetings all =20 I received a new 'puter for Xmas so I moved all my networked = 'chines up a notch. I re-did all the networks ...etc....everything works great.. I can access all computers and their resources from each other. The Two = main ones I'm concerned about are SDR and Winquake (Original Machine = names huh?) from sdr i can access Winquake and all it's files etc . I = can write files, make new directories, delete files and = directories.Everything seems as good as could be. I have set up sdr to 'Net Use F: \\c209139b\quake_d'=20 ( c209139b is the actual computer name on the network for the winquake = machine. ) and it works fine with sdr.ini set up to point all it's saved files to it's own hard drive = everything works great. but if I set sdr.ini up to point to the Winquake = machine all is not well.. sdr starts and runs normally for about 7 seconds then freezes, followed = by having to reset the machine... I am at having no luck from there... I have checked all IRQ's , = addressing etc and there are no conflicts on both machines. SDR has only = bare minimum boards video, IDE/floppy/ser 1/network card/ and PCL 711 anyone have ANY suggestions? thanks tom
 
Greetings all
 
     I received a = new 'puter=20 for Xmas so I moved all my networked 'chines up a notch.
    I re-did all the = networks=20 ....etc....everything works great..
I can access all computers and their=20 resources from each other.  The Two main ones I'm concerned = about are=20 SDR and Winquake (Original Machine names huh?) from sdr i can access = Winquake=20 and all it's files etc . I can write files, make new directories, delete = files=20 and directories.Everything seems as good as could be.
I have set up sdr to 'Net Use F: \\c209139b\quake_d' =
( c209139b is the=20 actual computer name on the network for the winquake machine. ) and it = works=20 fine
 
with sdr.ini set up to point all it's = saved files=20 to it's own hard drive everything works great. but if I set sdr.ini up = to point=20 to the Winquake machine all is not well..
sdr starts and runs normally for about = 7 seconds=20 then freezes, followed by having to reset the machine...
 
I am at having no luck from there... I = have checked=20 all IRQ's , addressing etc and there are no conflicts on both machines. = SDR has=20 only bare minimum boards
video, IDE/floppy/ser 1/network card/ = and PCL=20 711
anyone have ANY = suggestions?
 
thanks
tom
Subject: "Giant Seismometer" From: John Hernlund hernlund@............ Date: Tue, 26 Dec 2000 16:12:48 -0800 Hi Everyone, I came across some really good stuff at AGU last weekend. One item that will interest you all is the construction of what may be the largest seismometer ever. A friend of mine named Steve Gao (at Kansas State) got together with a fellow engineering professor at KSU that can measure the length of fiber optic cable very accurately using a simple reflection technique (the technology is in the sending and receiving unit). They got an NSF grant to go around hooking this thing up to existing fiber optic networks and monitoring the strain across the fiber optic cable in time. They haven't yet conducted their first major experiment, but they expect to measure a lot of subtle effects. The advantage of this device is that it is truly broadband, and the technique can conceivably sample at any frequency without any frequency dependence. The sending/receiving unit costs around $10,000 to build, which is cheaper than many commercial broadband seismometers. Since most of the fiber optic cables in the ground for telecommunications are not in use (due to super-high bandwidth) they can go around renting an optic cable here and there. Their biggest ambition is to wire up a huge network of these things, especially in the area of the San Andreas where strain precursors may be looked into for a very low price. Traditional strain measurement at the San Andreas has consisted of laser interferometry through the air, which turns out noisy/messy data and is extremely expensive. Plus the desired accuracy can be achieved in the fiber by simply increasing the length of the cable you use, since the error over time will be independent of the fiber length. If the instrument yields an error of X (for example), and you wish to measure a strain above a noise level E, then just hook it up to a cable of length L = X/E. For them, X is typically less than 1 mm, so for a 10 km cable the lower limit of effective measurement is 10^(-7), which gives them a very useful range. Over time these things will become more accurate and less expensive to use... Cheers! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ULF From: Arie Verveer ajbv@............ Date: Wed, 27 Dec 2000 09:28:03 +0800 Hi, In Larry's event folder are two files 001225a.au2, 001225a.au4 that show the ULF magnetic background and a seismic trace of the Mb5.8 event 1231Km south of my location. The magnet trace for that day shows some solar interaction. Though the trace shown here is the only long wave magnetic variations for that day. Its interesting to ponder if this is associated in some way. Maybe a precursor or a trigger or just a coincidence. Since I've been monitoring both the seismic and ULF magnetic background the device has logged a few potential triggers on local quakes and far less detection of possible precursor's. But if you look at the frequency of quakes then the data can be said to be statically insignificant. It should be said that it may be my equipment that's not sensitive enough or my location is not close enough to a fault line. Also it would be better to conduct this type of experiment during a solar quiet time. One thing I have noticed that during intense activity of the magnetic field the seismic trace shows "pulses" of induced noise. On both amateur and professional seismometers. Cheers and good new Millennium. Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "Giant Seismometer" From: Bob Smith bobsmith5@........ Date: Wed, 27 Dec 2000 07:28:13 -0500 John -- I admire the creative process that thought this one up!!! I wonder, however, if there isn't a basic flaw in this plan. I would expect that any such fiber optic cables are installed with generous numbers of expansion loops. Thus, there would be very little variation in strain in conjuction with geological events. However the following does not mention the mechanism which produces said strain so I may have missed the point here. I hope they succeed, best to all, Bob Smith John Hernlund wrote: > > Hi Everyone, > I came across some really good stuff at AGU last weekend. One > item that will interest you all is the construction of what may be the > largest seismometer ever. A friend of mine named Steve Gao (at > Kansas State) got together with a fellow engineering professor at > KSU that can measure the length of fiber optic cable very accurately > using a simple reflection technique (the technology is in the sending > and receiving unit). They got an NSF grant to go around hooking this > thing up to existing fiber optic networks and monitoring the strain > across the fiber optic cable in time. They haven't yet conducted their > first major experiment, but they expect to measure a lot of subtle > effects. The advantage of this device is that it is truly broadband, > and the technique can conceivably sample at any frequency without > any frequency dependence. The sending/receiving unit costs around > $10,000 to build, which is cheaper than many commercial broadband > seismometers. Since most of the fiber optic cables in the ground for > telecommunications are not in use (due to super-high bandwidth) they > can go around renting an optic cable here and there. Their biggest > ambition is to wire up a huge network of these things, especially in > the area of the San Andreas where strain precursors may be looked > into for a very low price. Traditional strain measurement at the San > Andreas has consisted of laser interferometry through the air, which > turns out noisy/messy data and is extremely expensive. Plus the > desired accuracy can be achieved in the fiber by simply increasing the > length of the cable you use, since the error over time > will be independent of the fiber length. If the instrument yields an > error of X (for example), and you wish to measure a strain above a > noise level E, then just hook it up to a cable of length L = X/E. For > them, X is typically less than 1 mm, so for a 10 km cable the lower > limit of effective measurement is 10^(-7), which gives them a very > useful range. Over time these things will become more accurate and > less expensive to use... > > Cheers! > > John Hernlund > Department of Earth and Space Sciences > University of California, Los Angeles > hernlund@............ > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "Giant Seismometer" From: D Collins dcollin@........... Date: Wed, 27 Dec 2000 09:14:11 -0700 At 05:28 AM 12/27/00 , you wrote: >John -- > >I admire the creative process that thought this one up!!! > >I wonder, however, if there isn't a basic flaw in this >plan. I would expect that any such fiber optic cables are >installed with generous numbers of expansion loops. Thus, >there would be very little variation in strain in conjuction >with geological events. However the following does not >mention the mechanism which produces said strain so I may >have missed the point here. Yes, as an old fiber design engineer for the phone company, our general rule of thumb was to go about three manholes and put in a slack loop. This insured that ample cable would be available for re-splicing in the event of a dig-up or some other problem. Fiber optic cables are the strongest digger attractor in the world 8<) Darrell __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "Giant Seismometer" From: Mike Lozano mikel@............... Date: Wed, 27 Dec 2000 10:59:56 -0600 Kind of like 'mobile homes' attracting tornadoes! Mikel D Collins wrote: > At 05:28 AM 12/27/00 , you wrote: > >John -- > > > >I admire the creative process that thought this one up!!! > > > >I wonder, however, if there isn't a basic flaw in this > >plan. I would expect that any such fiber optic cables are > >installed with generous numbers of expansion loops. Thus, > >there would be very little variation in strain in conjuction > >with geological events. However the following does not > >mention the mechanism which produces said strain so I may > >have missed the point here. > > Yes, as an old fiber design engineer for the phone company, our general > rule of thumb was to go about three manholes and put in a slack loop. This > insured that ample cable would be available for re-splicing in the event of > a dig-up or some other problem. Fiber optic cables are the strongest > digger attractor in the world 8<) > > Darrell > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: fiber optic strainmeters From: sean@........... Date: Wed, 27 Dec 2000 13:29:41 -0600 (CST) Darrell, John, and co., Yes, fiber cables are major backhoe attractors. I operate a 3 km link for a super broadband station in a state park, with three 1 km lengths between the cavern and the visitor center. The cable was installed in 1988, so they pretty well know where it is. It has had close calls before, but the double armor has saved it. Last spring they called me to exactly locate the cable, which I have marked with magnets every 10 m, but they went ahead and tore it up as I was driving there. The break was 100 m from a splice pedestal, so by replacing 110 m of the cable, I ended up with the loss of only one additional splice. For the idea of using terrestial fibers, we can presume that long distance runs will be used. These are popularly installed using abandoned oil and gas lines as conduits, and the thinking for the strainmeter is that simple friction will convey the change of length of the earth to the conduit and then to the fiber cable lying loosely inside: the change is very small, and distributed over a relatively large distance. At slack points, there would be no coupling, but these would represent a very small portion of the length. And although such pipes/conduits are buried at least a meter, temperature is a major concern; it changes the index of the glass, so it can be determined; at CCM, the very shallow (.5 m) cable changes its loss by about 4 db (out of about 20 db total loss) from summer to winter. Of further interest in fiber optic strainmeters for geodetic strain measurements is a plan to use "extra" fibers in the undersea cables. Since much of the earth is oceanic and off limits to practical seismic instruments, measuring strain across the oceans would be a great contribution to geodynamics. But a feature of undersea fiber cables is that the optical signal still has to be regenerated every 5 to 15 kilometers. So the plan is to use every cable segment as a separate strainmeter, with appropriate instrumentation at each cable amplifier node, and with the data of each segment multiplexed to a continuous fiber, like the cable's state-of-health/control fiber. But this would be very expensive, even assuming a cable owner would share the fiber bundle and allow the inclusion of the interferometers gratis. The first fiber optic strainmeters were developed by UCSD at the Pinon Flat strain observatory (PFO) about a decade ago. They were installed in boreholes drilled at a 45 degree angle, and used a complex tensioning device. They had a resolution of about 10^-6, limited by the slanted borehole length. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ULF From: "meredith lamb" mlamb1@.......... Date: Wed, 27 Dec 2000 13:26:05 -0800 Arie Verveer wrote: > Hi, In Larry's event folder are two files 001225a.au2, 001225a.au4 that > show the ULF magnetic background and a seismic trace of the Mb5.8 event > 1231Km south of my location. The magnet trace for that day shows some > solar interaction. Though the trace shown here is the only long wave > magnetic variations for that day. Its interesting to ponder if this is > associated in some way. Maybe a precursor or a trigger or just a > coincidence. Hi Arie, I did check Guam and Boulder, Colorado....they did show a beginning solar geomagnetic signal for the time of your geomagnetic gram, but it was a long slow variation over a much longer period of time....then it fluxed around abit for hours thereafter. I've little or no background experience with your magnetometer coil design.....but....it seems to cough up some questions for more simpler designs....whether its practical or not. Perhaps you or someone else can interject the fallacy of my thoughts: Would it be worthwhile to use, say, a number of coils (relay or what not), into a number of parallel hookups, with say a steel rod through the center holes. Presume a low overall resistance would be better than a high overall resistance. One might wrap MU foil over or around the rod to enhance its properties...or to close any coil/rod gap? Would it make a difference to say use a separate overhead or side shield/s separate from the instrument for some local prevention of some electromagnetic noise sources? Kind of like a parbolic antenna pointing downward to pickup the earths signal reaction and not primarily the solar activity overhead. Presume the coil ROD is electrically insulated from earth, or....is it? Just musings, Regards, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fiber optic strainmeters From: John Hernlund hernlund@............ Date: Wed, 27 Dec 2000 12:17:48 -0800 sean@........... wrote: > For the idea of using terrestial fibers, we can presume that long distance > runs will be used. These are popularly installed using abandoned oil > and gas lines as conduits, and the thinking for the strainmeter is that > simple friction will convey the change of length of the earth to the > conduit and then to the fiber cable lying loosely inside: the change > is very small, and distributed over a relatively large distance. At > slack points, there would be no coupling, but these would represent a > very small portion of the length. And although such pipes/conduits are > buried at least a meter, temperature is a major concern; it changes the > index of the glass, so it can be determined; at CCM, the very shallow > (.5 m) cable changes its loss by about 4 db (out of about 20 db total > loss) from summer to winter. Yes, this is something they will have to address. I think their first mission is to measure the tides over a large area. This kind of data can be quite valuable because the gravitational forces which induce the tides are very well known, thus the measured data can be used to get material properties if the measurement is sensitive enough. > Of further interest in fiber optic strainmeters for geodetic strain > measurements is a plan to use "extra" fibers in the undersea cables. > Since much of the earth is oceanic and off limits to practical > seismic instruments, measuring strain across the oceans would be > a great contribution to geodynamics. This would be fanstastic. It would actually be perfect to measure strain in segments across the Atlantic to see how it varies perpendicular to the ridge. I would be interested in seeing how strain accumulated at the ridge propagates outward, and how it varies in time and space. It would certainly be nice to get some real numbers to compare with our numerical models. > The first fiber optic strainmeters were developed by UCSD at the > Pinon Flat strain observatory (PFO) about a decade ago. They were > installed in boreholes drilled at a 45 degree angle, and used a > complex tensioning device. They had a resolution of about 10^-6, > limited by the slanted borehole length. The engineering fellow currently uses fiber optic strain meters on structures such as bridges. They have been very useful for him in measuring a structure's response to wind and other forces. Cheers! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Engineering computer article From: "meredith lamb" mlamb1@.......... Date: Wed, 27 Dec 2000 14:10:00 -0800 See a article on a computer network for engineering and seismic use, being planned. (As of dec 27th, 2000) http://www.sciencedaily.com (the 4th "headline" down) Am not real sure, but I believe the NEIC is also revising their current computers (or planning for such); but its not discussed in that article. Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fiber optic strainmeters From: barry lotz gbl@....... Date: Wed, 27 Dec 2000 08:27:15 -0800 John I had a couple of questions. I was wondering how the cable would be supported ( or not) ? Would there be friction between the conduit and cable due to bends in the cable or gravity? I know in prestressed concrete there are pretty sizable losses in tension due to friction, though I realize the magnitude of forces are considerable different.. I'm not familiar with how the longer length cables are suspended or supported. It would seem that even short suspended cables would have a catanary (spelling?) shape which would change with distance between supports and thus the cable might not stretch the same amount as the ground moves. I guess could be calibrated and the strains corrected. I am also very interested in your progress and findings. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fiber optic strainmeters From: Mark Robinson other@............... Date: Thu, 28 Dec 2000 17:05:20 +1300 Asuming they are using some time domain reflectometry technique, I would assume that it could be done on a live comms cable. Fibre gyroscopes are popular on high end projects ... they measure rotation in accuracies of the order of the number of wavelengths around their circumference. they split the input light, the two signals going in opposite direction around a circle. the recombination of the light gives pulses with rotation ... I can't remember how they achieve quadrature. Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fiber optic strainmeters From: John Hernlund hernlund@............ Date: Thu, 28 Dec 2000 19:41:35 -0800 Mark Robinson wrote: > Asuming they are using some time domain reflectometry technique, I would > assume that it could be done on a live comms cable. Apparently a special reflector has to be placed at one end of the line. It is a time-of-flight measurement that they are using. > Fibre gyroscopes are popular on high end projects ... they measure > rotation in accuracies of the order of the number of wavelengths around > their circumference. they split the input light, the two signals going > in opposite direction around a circle. the recombination of the light > gives pulses with rotation ... I can't remember how they achieve > quadrature. For some reason that I am not aware of these guys have abandoned any kind of interferometric technique. Perhaps it is too expensive? I understand the math and physics behind this stuff, but as far as the engineering end goes I have no clue... John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fiber optic strainmeters From: John Hernlund hernlund@............ Date: Thu, 28 Dec 2000 20:05:04 -0800 barry lotz wrote: > John > I had a couple of questions. I was wondering how the cable would be > supported ( or not) ? Would there be friction between the conduit and cable due > to bends in the cable or gravity? In a smaller version they are building (without slack loops) they are simply fixing each end, which is probably the best way. The small strains they are interested in looking at will probably produce a very small force per unit length which may be lower than the static friction force. > I know in prestressed concrete there are > pretty sizable losses in tension due to friction, though I realize the magnitude > of forces are considerable different.. Yes, we used to have problems with hydraulics in our high pressure equipment due to the friction on the rams. > I'm not familiar with how the longer > length cables are suspended or supported. It would seem that even short > suspended cables would have a catanary (spelling?) shape which would change > with distance between supports and thus the cable might not stretch the same > amount as the ground moves. I think it is not suspended at all, but lays in whatever conduit it travels through. > I guess could be calibrated and the strains corrected. I am also very interested > in your progress and findings. I am not connected with this particular project, and I only know what I know about this from a dinner conversation I had with this guy at AGU. I am quite interested in seeing the data that may potentially come out of these types of experiments though. Lately I am working on computer models...mantle convection, fluid dynamics and elasticity type stuff. Cheers! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Reliable cheaper magnets! From: hewei Date: Fri, 29 Dec 2000 12:17:40 +0800 Gentlemen, We are a newly established professional magnets supplier situated in mainland China and can supply an extensive range of magnet products with very competitve price.Our factories are ISO9000 certified and reliable. Our most competitve magnets are high Grade NdFeB(N45,N48,N50) and Ceramic Ferrite. Please visit our web: http://cadee.top263.net for products catalogue. We want to establish business with your company. We are quite sure of your more profit to do business with us! Sincerely yours, hewei Manager of Cadee Technology email: cadee@........ voice:+86 23 62820911 fax:+86 23 62812123 address:1F No.59 xiangsui Rd.Nanpin Chongqing China ,400060 Subject: Re: Lehman seismograph From: "Ed Ianni" edwianni@........ Date: Sat, 30 Dec 2000 10:27:55 -0500 Subject: Re: Lehman seismograph > Hi PSN members. Thanks for welcoming me to the PSN network. I have recently decided to build the Lehman seismograph.. I have completed the Transducer part of my "Lehman" and I am about to build an amplifier (which I dread[can they be purchased or "requisitioned" anywhere])?. I have a small problem though and I hope that you may have some thoughts on it. The only> feasable place for me to place the seismograph seems to be in my basement > which has a thin carpet in it over a concrete floor. Do I need to cut the > carpet away(the size of the Lehman base)? What do you think of the idea of > using VERY LARGE and SHARP screws that would penetrate the carpet and they > can also be used for Leveling? I have heard of some people using their > seismographs on other than the ground floor (wouldn't the waves be baffled/diminished)? > Any thoughts would certainly be appreciated. Thank you very much, Ed. > > > > > > > > > ----- Original Message ----- > From: "Larry Cochrane" > To: "Ed Ianni" > Sent: Monday, December 18, 2000 12:41 AM > Subject: Re: Lehman seismograph > > > > Ed, > > > > First go back to the knife edge. Since a Lehman is a horizontal sensor you > > only want horizontal movement of the boom. To get the boom to stabilize > you > > need to position the top pivot point (where the wire meets the holder) > > slightly before the bottom pivot point (the knife edge). As the angle > > becomes straight up and down the boom will become more unstable. This is > > also how you set the period. The period will increase as the angle becomes > > more straight up and down. You can adjust the angle by lifting up the back > > end of the sensor. This will change the top and bottom angle. First start > > with a large angle and no damping. The boom should come too rest in the > > center of the sensor. As you lower the backend of the sensor the > oscillation > > period should increase. At some point the boom will become unstable. At > that > > point increase the angle a little and check the period. It should be > between > > 10 and 20 seconds. > > > > Hope this helps and good luck. > > > > -Larry Cochrane > > Redwood City, PSN > > > > ----- Original Message ----- > > From: Ed Ianni > > To: cochrane@.............. > > Sent: Saturday, December 16, 2000 7:28 PM > > Subject: Lehman seismograph > > > > > > Dear Mr. Cochrane; > > I am building the Lehman home seismograph. I am unable to get the > > boom stabilized although everything is level. I have used a "knife point" > > and a "rounded end" but the centering of the boom remains difficult and > > inconsistent. Any suggestions would help. Thank You Very Much. Ed. > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: "Larry Conklin" lconklin@............ Date: Sat, 30 Dec 2000 11:25:36 -0500 Ed, I have my SG sensor sitting on my concrete basement floor, and it is working ok. It has rather small leveling screws and I was having a problem with the thing getting out of level for no apparent reason, every day or so. I solved the problem by gluing a couple of aluminum plates to the concrete for the leveling screws to sit on. I'm guessing that adjusting the leveling screws was grinding the concrete surface and leaving a little dust under the screw that made the foundation a little "flakey". I suspect that unless your leveling screws are completely free of the carpet you're likely to have similar problems. Larry Conklin ----- Original Message ----- From: "Ed Ianni" To: Sent: Saturday, December 30, 2000 10:27 AM Subject: Re: Lehman seismograph > Subject: Re: Lehman seismograph > > > > Hi PSN members. Thanks for welcoming me to the PSN network. I have > recently decided to build the Lehman seismograph.. I have completed the > Transducer part of my "Lehman" and I am about to build an amplifier (which I > dread[can they be purchased or "requisitioned" anywhere])?. I have a small > problem though and I hope that you may have some thoughts on it. The only> > feasable place for me to place the seismograph seems to be in my basement > > which has a thin carpet in it over a concrete floor. Do I need to cut the > > carpet away(the size of the Lehman base)? What do you think of the idea of > > using VERY LARGE and SHARP screws that would penetrate the carpet and they > > can also be used for Leveling? I have heard of some people using their > > seismographs on other than the ground floor (wouldn't the waves be > baffled/diminished)? > > Any thoughts would certainly be appreciated. Thank you very much, Ed. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: "Ed Ianni" edwianni@........ Date: Sat, 30 Dec 2000 11:26:45 -0500 Thanks a lot Larry. I appreciate your answer. Ed. ----- Original Message ----- From: "Larry Conklin" To: Sent: Saturday, December 30, 2000 11:25 AM Subject: Re: Lehman seismograph > Ed, > > I have my SG sensor sitting on my concrete basement floor, and it is working > ok. It has rather small leveling screws and I was having a problem with the > thing getting out of level for no apparent reason, every day or so. I > solved the problem by gluing a couple of aluminum plates to the concrete for > the leveling screws to sit on. I'm guessing that adjusting the leveling > screws was grinding the concrete surface and leaving a little dust under the > screw that made the foundation a little "flakey". I suspect that unless > your leveling screws are completely free of the carpet you're likely to have > similar problems. > > Larry Conklin > > > ----- Original Message ----- > From: "Ed Ianni" > To: > Sent: Saturday, December 30, 2000 10:27 AM > Subject: Re: Lehman seismograph > > > > Subject: Re: Lehman seismograph > > > > > > > Hi PSN members. Thanks for welcoming me to the PSN network. I have > > recently decided to build the Lehman seismograph.. I have completed the > > Transducer part of my "Lehman" and I am about to build an amplifier (which > I > > dread[can they be purchased or "requisitioned" anywhere])?. I have a small > > problem though and I hope that you may have some thoughts on it. The only> > > feasable place for me to place the seismograph seems to be in my basement > > > which has a thin carpet in it over a concrete floor. Do I need to cut > the > > > carpet away(the size of the Lehman base)? What do you think of the idea > of > > > using VERY LARGE and SHARP screws that would penetrate the carpet and > they > > > can also be used for Leveling? I have heard of some people using their > > > seismographs on other than the ground floor (wouldn't the waves be > > baffled/diminished)? > > > Any thoughts would certainly be appreciated. Thank you very much, Ed. > > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seis feet From: sean@........... Date: Sat, 30 Dec 2000 13:59:09 -0600 (CST) Ed, I agree with the suggestion that the leveling feet of your seis have to be free of the carpet. Recall that a horizontal sensor is very sensitive to tilt, so good contact with a solid foundation is essential. Stresses in the carpet would tend to drag the seismometer around. If you cut out a square piece of the carpet, be sure to save it in case it has to be replaced later. Large seismometers often use a rounded contact point for the seismometer feet: it is usually used in conjunction with small glass plate placed under it on the pier. The glass minimizes lateral torqueing as the screw is turned, and also allows the contact point to slide freely as the base expands with temperature. Disadvantage: a careless move or nasty quake can slide the foot of the seis off of the glass plate. Smooth >Glossy< glazed ceramic tiles will also work. I use them for the top surface of small piers. They can be grouted or thinly epoxied in place, or just simply "ground in" by rotating them under pressure to make a consistent contact with the concrete if the surface is smooth enough. And remember to orient your horizontal seis with the mass movement parallel to the adjacent foundation wall, (ie. the boom at a right angle to the wall) so as to minimize tilting from loading and warping of the basement floor. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: "George Harris" gjharris@............. Date: Sat, 30 Dec 2000 12:21:21 -0800 ----- Original Message ----- From: Ed Ianni To: Sent: Saturday, December 30, 2000 7:27 AM Subject: Re: Lehman seismograph Ed, I had the same problem, since I wanted to mount the unit in the carpeted den on a concrete slab. I drilled three1/4 inch holes through the carpet, making sure that I did not catch the fibers in the drill. I then injected a little epoxy into the holes and inserted 1/4 inch screws. Onto this I mounted a plate with nuts above and below. It seems to be a very stable platform. I hope that the screws will be removable by use of a wrench when necessary (don't use too much epoxy-perhaps I should have greased the screws first). George Harris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: johnc c cole johnccole1@........ Date: Sat, 30 Dec 2000 15:23:03 -0600 Ed You received some good advice from the group. I have nothing to add to what they suggested but, I would not cut a plug out of the carpet for the leveling screws . Cut a two or three inch slit where the leveling legs touch the floor. After you change your mind about the exact location. glue the carpet back together with a small amount of super glue or carpet mastic. Good luck. john ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: "Larry Conklin" lconklin@............ Date: Sat, 30 Dec 2000 17:27:16 -0500 > After you change your mind about the exact > location. glue the carpet back together with a small amount of super glue > or carpet mastic. Good luck. boy, that sounds familiar! I moved my sensor about 8 times before I settled on a spot that was sufficiently isolated from foot traffic on the floor above. If I'd left a foot square hole in a carpet behind in all of the previous trial locations my marriage would have been over long ago. Larry Conklin __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seis feet From: "Charles R. Patton" charles.r.patton@........ Date: Sat, 30 Dec 2000 17:28:50 -0800 Sean, A question. You mention the use of ceramic or glass plates for bases, but a problem of slipping off in strong quakes. In =93Building Scientifi= c Apparatus=94 by Moore, Davis and Coplan there is a discussion of kinemati= c design and in particular being able to replace (and replace) an item in a stable position exactly. The essense is to use three feet, each foot being a ball bearing. The plate they sit on is the trick. One foot rests in a three sided pyramidal depression, the second is in a V-groove generally aimed at the pyramidal depression, and the last bearing rests on a flat surface. These resting points could easily be constructed out of glass or ceramic tile pieces. The result would be a very stable mounting where the object mounted would be very resistant to sliding off the pedestal except in the most violent episodes. Do you think there are other problems I=92m missing? Charles R. Patton __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman seismograph From: "David Saum" DSaum@............ Date: Sun, 31 Dec 2000 12:40:53 -0500 > The only feasable place for me to place the seismograph seems to be in my basement > which has a thin carpet in it over a concrete floor. Do I need to cut the > carpet away(the size of the Lehman base)? What do you think of the idea of > using VERY LARGE and SHARP screws that would penetrate the carpet and they > can also be used for Leveling? I have heard of some people using their > seismographs on other than the ground floor (wouldn't the waves be > baffled/diminished)? I do not think the carpet should be a problem unless it is thick enough to make leveling unstable. My Lehman sits on a carpeted basement floor. I do not seem to have any sensitivity problem with this arrangement. I originally had flat ended leveling bolts contacting the carpet but I found that when they were adjusted they snagged bits of carpet, and that made leveling difficult. This was fixed by putting round headed "cap nuts" on the ends of the bolts. It is difficult for me to see why a carpet would attenuate the coupling of the pendulum with the typical 10 to 20 second seismic signals. It seems more likely that higher frequency noise that is not of interest would be attenuated by the carpet. I do have several bricks on top of my Lehman base for added stability. Although the leveling drifted for the first week after startup, it has not required adjustment in months. Ciao, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: more seis feet From: sean@........... Date: Sun, 31 Dec 2000 13:55:55 -0600 (CST) Charles, I have seen such arrangements for exact repositioning in kinematic mounts for telescope objective instruments and some differential GPS monuments. But I was being a bit hyperbolic in suggesting that a quake would slide an LP seis (but speaking from experience in noting that > I < might shove it off the glass plates). We had an Mb 8.6 at Adak in 1986, 30 km from the main vault that indicated almost half of g on the seismoscope; the LP seismometers slid a couple of mm, as indicated by tracks in the dust on the glass plates, and remained functional but tilted off center by several mm. Regarding the carpet discussion: I would not follow the advice that an LP horizontal with sufficient sensitivity can be operated on top of a carpet, especially a horizontal with its very high tilt sensitivity. By "sufficient sensitivity" I mean the ability to routinely record the 6-second microseism background with at least a 10:1 signal to noise ratio. These typically run from 2 to 10 (during a storm) microns peak-to-peak. Magnitude formulas want the wave amplitude entered in milli-microns (nanometers), so smaller events have to be read over the mean of the microseisms. It is not a matter of spectral sensitivity, since all the seismic waves of interest are much larger than the instrument (a 1 second surface wave is 2+ km long). But the P-wave of a M 5.7 near Mexico city is only a few times larger in amplitude than the microseisms at St. Louis, and wouldn't be seen on a less sensitive system. If I don't see the microseisms I try to find out what went wrong. Seismologists have not gone to all the effort of piers, vaults, proximity to bedrock, etc, because they have too much money (fat chance), but to reduce the noise of the instrument environment. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L)