Subject: re: more seis feet From: "David Saum" DSaum@............ Date: Mon, 1 Jan 2001 12:14:14 -0500 > 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. Some of us are operating our systems under constraints that rich seismologists never dreamed of. For instance my Lehman is on the carpeted slab in an office building and my landlord would not be pleased if I damaged the carpet. I can imagine other non ideal locations such as upper floors in buildings, but they may be the only available or most convenient location. Perhaps these "less than ideal" locations should not be eliminated without an experimental test since there seems to be no basic physics that excludes them a priori. The two most important empirical tests seem to be: 1. is the level stable over time? 2. can it detect microseisms? My one data point with a Lehman on carpeted floor suggests that detecting microseisms is no problem, and long term level stability is not a problem if you are willing to put up with noise spikes from occasional floor tilts due to building operation and occupancy. BTW: I liked the idea of resting the entire Lehman on a slab of glass. That might make the carpet even less of a factor. I will give it a try. Ciao, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more seis feet From: "Charles R. Patton" charles.r.patton@........ Date: Mon, 01 Jan 2001 09:30:43 -0800 A further thought on a stable platform on carpet might be to drive three nails thru the carpet into the slab or floor. Done carefully the nails would leave relatively small holes that would be easy to cover by re-brushing the carpet after their removal at some further date. Top the nails with ball bearings that are glued on (or previously brazed on). Then make a platform from a hardened material with the kinematic depressions as I previously described, except do it on both sides. Place the platform on the nail tops, then your seimo on the platform. Everything would be locked together with a kinematic mount. Charles R. Patton __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: instrument siting From: sean@........... Date: Mon, 1 Jan 2001 16:06:47 -0600 (CST) Dave, You are way out of line and very mis-informed in stating that seismologists are "rich". Over three decades I have seen amazing self sacrifice and personal investment on the part of seismologists to achieve the data quality that is required. The current new generation of broadband instruments are so expensive that often the qualified technical personnel to install and operate them have to be left out of the budget, and volunteers have to try to do the work. The only people who had adequate funding was the AFOSR (Air Force Office of Scientific Research) during the cold war for installing seismic systems for nuclear test detection. Even the current CBTB (comprehensive test ban treaty) verification instrumentation funding is very limited. But for the most part, most seismologists have to do most of the work of preparing sites and installing instruments themselves because they cannot afford commercial contractors. And after a site is established, the continuing operation is up to the scientists' dedication, like paying the postage to mail data tapes. We "rich seismologists" of course have never "dreamed of" such poor sites as a carpeted floor, because in the past 50 years someone has tried it and found the idea to be a dud compared with what their colleagues were getting from more carefully prepared (and probably more difficult) sites. Even in the 20's era of mechanical-optical- photo-recording instruments of quite low sensitivity, the quietness and isolation of a pier in a vault was desired. Our old SLM vault at St. Louis U. was installed deep under the lobby of a new gym in 1923 when a Jesuit (Fr. Macelwane) found bedrock there and twisted other Jesuit arms to get it installed for free. As for the site of a long period instrument, particularly a horizontal, I would encourage everyone to make every effort to optimize the site conditions. I don't think "easy" or "convenient" are valid criteria if you want to record more than a few large quakes per year, like todays Ms 7.2 in the Philippines, which should have been very well recorded by all the PSN instruments. The monthly-or-so M 6.0 events will be about 6% of this amplitude, and should also be clearly recorded just to keep up interest (= maintenance/adjustment). I routinely run preliminary tests of instruments in my lab on the third floor of a very sturdy building (it was designed for 8 floors that never got built because the Univ ran out of $$). Even adjacent to a 30" square pillar, my lab floor runs at about a continuous Ms 3.0 quake. The whole building tilts several micro-radians daily as the sun warms the south side. Even the test pier in the basement is swamped with the noise of the AC fans, the elevators, the streets, etc. My only "good" test site is 40 km away in a WWII munitions bunker, (black powder on the floor) but I still see the noise of the interstate about 0.5 km away. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more seis feet From: Mark Robinson other@............... Date: Tue, 02 Jan 2001 12:19:06 +1300 Hi all In optical mounts, such as those for the mirrors in an ion laser, there are some refinements which may be of some use in this application. The laser application has similar or greater requirements for accuracy and stability. The principle difference is that the levelling is done between two pieces that are structural to the instrument, and that these two pieces are held in tight coupling to each other. At each of the three mounting points the two plates are held together by suitably strong springs, and pulled apart by the adjusting screws. In general one point is more or less fixed, while the other two points provide adjustment in the x and y dimensions. It would seem natural to put the fixed point under the mast of a lehman. An arrangement of this type would allow the bottom plate to the screwed firmly to whatever surface the instrument is meant to be measuring, and the rest of the instrument adjusted relative to this. a further refinement observable on laser mirror mounts are physical restraints preventing the moveable plate from being displaced by gross shocks. a screw with a waskher and a spacer under it's head through a clearance hole in the adjustable plate, screwed firmly into the base plate is common. The springs are usually mounted to bars set in grooves across holes in both plates. The bearing points are usually ball headed. The fixed point is commonly a ball bearing set over holes in each plate. A well engineered arrangement such as this provides excellent coupling between the instrument and the substrate, as well as fine and repeatable adjustments. and it should stay very firmly put in even a very large shake. I hope this is understandable and helpful. Happy New Year everyone Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: instrument siting From: "David Saum" DSaum@............ Date: Tue, 2 Jan 2001 12:27:00 -0500 I seem to be able to see distant quakes down to about 6 although my Lehman sits on a carpeted basement slab in a noisy environment. Note that I am still debugging my system, and I use Amaseis and WinQuake software. Amaseis seems to screw up some of the file headers passed to Winquake 1/1/01 MINDANDAO, PHILIPPINES 7.2Ms daily Amaseis display with 0.08 LP Hz http://www.infiltec.com/seismo/010101.jpg Winquake LP @ 0.08 Hz http://www.infiltec.com/seismo/010101C.jpg 1/1/02 MINDANDAO, PHILIPPINES 6.2Ms daily Amaseis display with LP @ 0.08 Hz http://www.infiltec.com/seismo/010102.jgp Winquake LP @ 0.08 Hz http://www.infiltec.com/seismo/010102D.jpg Winquake with no LP (analog 4 hz LP) http://www.infiltec.com/seismo/010102C.jpg As you can see there is a lot of slab tilting going on during the day when the building is occupied, and the 6 sec noise is pretty high recently so I get a lot better seismic signal with a LP @ 0.08 Hz. And lucky for me all big quakes occur at night! Ciao, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismometers on ebay From: BOB BARNS roybar@........ Date: Thu, 04 Jan 2001 10:09:18 -0500 Hi gang, There are 3 seismometers currently on sale on ebay. These are said to be Kinemetrics SV-1 5 sec verticals. They look very good. The current price is about $100. Search on "kinemetrics" There is only 12 hrs. left for these auctions. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Seismometers on ebay From: "Giovanni Rotta" rottag@.......... Date: Thu, 4 Jan 2001 17:13:25 +0100 Figlio mio.... Sai usare il compattatore ? Grazie dell'invio, gio ----- Original Message ----- From: BOB BARNS To: PSN mail list Sent: Thursday, January 04, 2001 4:09 PM Subject: Seismometers on ebay > Hi gang, > There are 3 seismometers currently on sale on ebay. These are said to > be Kinemetrics SV-1 5 sec verticals. They look very good. The current > price is about $100. > Search on "kinemetrics" > There is only 12 hrs. left for these auctions. > 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. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: Seismometers on ebay From: "Ted Blank" ted@.......... Date: Thu, 4 Jan 2001 11:43:56 -0500 Agree they look nice, but none has yet met the reserve price (unknown until somebody exceeds it). Regards, Ted Blank __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismometers on ebay From: "meredith lamb" mlamb1@.......... Date: Thu, 04 Jan 2001 08:18:30 -0800 Amazing....but there is actually 6 seismometers there. Items #'s: 1204280154 1204282138 1204282921 1204287703 1204288753 1204290420 and if you count the vibration analyzer 1204676062 which is over $1000.00 now, thats 7. All current auctions by "info@..............", out of Albequebue, New Mexico. Three short period vertical, one short period "omni-directional" seis, and two Long period units. The reserve on the long period (10-30 sec) units IS established at $200.00 I see. Should be interesting bidding.... Meredith Lamb BOB BARNS wrote: > Hi gang, > There are 3 seismometers currently on sale on ebay. These are said to > be Kinemetrics SV-1 5 sec verticals. They look very good. The current > price is about $100. > Search on "kinemetrics" > There is only 12 hrs. left for these auctions. > Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: The entire world, at night. From: Steve Hammond Shammon1@............. Date: Thu, 04 Jan 2001 13:03:53 -0800 Wow! Check this out. I'm sure there is some use for it in seismology. Be sure to scroll to see it all. http://antwrp.gsfc.nasa.gov/apod/image/0011/earthlights_dmsp_big.jpg Regards, Steve Hammod PSN Aptos, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Heilplot Software for SDR files From: Arie Verveer ajbv@............ Date: Fri, 05 Jan 2001 13:33:44 +0800 Hi, I have just completed a program that converts the data files (ChanX.xxx) from Larry's "SDR" program into 24 hour heilplots. If you have a lot of raw "SDR" data and would like to convert them into a "GIF" file heilplot then the program can be found at: (Click "Download PSN related Software" at the bottom of the page) http://www.iinet.net.au/~ajbv/ This program is very memory intensive and runs in a “dos” environment on a window's machine. WIN 95/98/NT/? It would be wise to read the instructions before using the program. There are many options in the program, from digital filtering, scaling to wild card selection on files. Its mode of operation depends on software switch settings in an initialization file called "SdrDrum.ini". This form of operation allows for greater flexibility as the program may be run via the operator, "scheduling" program or even a server "CGI" request. Whatever. The "GIF" file report can be viewed with your favorate "graphics viewer" or placed in your Web page. Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismometers on ebay From: RADIOTEL@....... Date: Fri, 5 Jan 2001 00:44:36 EST The company that sold the SV-1 and other seismometers on Ebay also have several Kinemetric SH-1 seismometers for sale. They can be reached at the following Email address: info@.............. Jim Allen Cerritos, Ca. The company that sold the SV-1 and other seismometers on Ebay also have
seve ral Kinemetric SH-1 seismometers for sale.  They can be reached at the
following Email address:  info@........... com    
Jim Allen
Cerritos, Ca. Subject: Re: Seismometers on ebay From: ChrisAtUpw@....... Date: Fri, 5 Jan 2001 13:42:14 EST In a message dated 04/01/01, mlamb1@.......... writes: > Amazing....but there is actually 6 seismometers there. Ebay Items #'s: > Three short period vertical, 1204280154 1204282138 1204282921 Kinemetrics SV-1 $327-80, $338-40, $360-88 > one short period "omni-directional" 1204287703 Geotech S-500 $151-88 > two Long period units. 1204288753, 1204290420 Geotech SL-220 $342-60, $296-40 Meredith, For reference, these were the final bids for the above equipment. Regards, Chris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: The entire world, at night. From: Bob Smith bobsmith5@........ Date: Fri, 05 Jan 2001 17:43:36 -0500 Steve -- Thank you! A truly amazing image. I see a couple of remarkable things. 1. Note the Suez canal, a brilliant trace of light from the Med on South. 2. I don't see an equivalent artifact for the Panama canal??? 3. The polar areas are marked by deep blue/violet colors. Is this a product of the imaging process (perhaps due to the temperature of the polar ice regions) ? Bob Smith Steve Hammond wrote: > > Wow! Check this out. I'm sure there is some use for it in seismology. > Be sure to scroll to see it all. > > http://antwrp.gsfc.nasa.gov/apod/image/0011/earthlights_dmsp_big.jpg > > Regards, Steve Hammod > PSN Aptos, CA > > __________________________________________________________ > > 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: The entire world, at night. From: Mark Robinson other@............... Date: Sat, 06 Jan 2001 12:21:14 +1300 > 3. The polar areas are marked by deep blue/violet colors. > Is this a product of the imaging process (perhaps due to the > temperature of the polar ice regions) ? I was given this image on a poster a few years ago. The coloured areas at the poles are intended to be a representation of aurora. Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: The entire world, at night. From: "Robert W. Avakian" ravakian@............ Date: Sun, 07 Jan 2001 00:33:25 -0600 I just checked my copy of the poster and, this image is probably not the same. The internet image seems to have higher resolution. Where, on the poster, there are blobs of light in the Saudi pennisula, the electronic image shows individual signaturesl. There also seems to be less agricultural burning in Africa. I'd think this is a more recent image suite. The aurora effeect on the paper image is missing on the web, but you can distinguish land and pack ice in the Arctic on the electronicimage! In any case, I'd love to get this image on paper Bob Avakian Mark Robinson wrote: > > 3. The polar areas are marked by deep blue/violet colors. > > Is this a product of the imaging process (perhaps due to the > > temperature of the polar ice regions) ? > > I was given this image on a poster a few years ago. The coloured areas > at the poles are intended to be a representation of aurora. > > 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. I just checked my copy of the poster and, this image is probably not the same.  The internet image seems to have higher resolution.  Where, on the poster,  there are  blobs of  light in the Saudi pennisula, the electronic image shows individual signaturesl.  There also seems to be less agricultural burning in Africa. I'd think this is a more recent image suite.

The aurora effeect on the  paper image is missing on the web, but you can distinguish land and pack ice in the Arctic on the electronicimage!

In any case, I'd love to get this image on paper

Bob Avakian

Mark Robinson wrote:

> 3.  The polar areas are marked by deep blue/violet colors.
> Is this a product of the imaging process (perhaps due to the
> temperature of the polar ice regions) ?

I was given this image on a poster a few years ago. The coloured areas
at the poles are intended to be a representation of aurora.

Mark
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

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Subject: Re: The entire world, at night. From: "David A. Nelson" davenn@........... Date: Mon, 8 Jan 2001 12:32:14 +1100 Happy new year all yup i am still in the land of the living.... been residing in australia for the last 12 months and as yet dont have a system set up... am going to have to build a lehman as very few local events to warrent short period geophones being used I am still doing updates and additions to the PSN members lists and maps so still send info to me... thankyou re the world nitetime view image... AWESOME the first thought that comes to my mind.. being an astronomer... is no wonder its hard to find dark observing skies in the western world these days!!! i may have to move to the outback of aussie haha.... dunno if my new wife would be agreeable to that plan tho cheers and may 2001 be a great year for u all Dave 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: Heilplot Software for SDR files From: Dick Webb dwebb2@.............. Date: Mon, 08 Jan 2001 21:05:52 -0500 Arie, your program works like a charm!. Actually, I processed the last six months of data and it only took about 20 minutes on a 450 MHz pentium. Thanks, Dick At 01:33 PM 1/5/01 +0800, you wrote: >Hi, I have just completed a program that converts the data files (ChanX.xxx) >from Larry's "SDR" program into 24 hour heilplots. If you have a lot of >raw "SDR" data and would like to convert them into a "GIF" file heilplot >then the program can be found at: > >(Click "Download PSN related Software" at the bottom of the page) > >http://www.iinet.net.au/~ajbv/ > >This program is very memory intensive and runs in a "dos" environment on a >window's machine. WIN 95/98/NT/? It would be wise to read the instructions >before using the program. There are many options in the program, from digital >filtering, scaling to wild card selection on files. Its mode of operation >depends on software switch settings in an initialization file called >"SdrDrum.ini". This form of operation allows for greater flexibility as the >program may be run via the operator, "scheduling" program or even a server >"CGI" request. Whatever. > >The "GIF" file report can be viewed with your favorate "graphics viewer" or >placed in your Web page. > > >Cheers > >Arie >__________________________________________________________ > >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: LP filters, A/D bits and SPS From: "David Saum" DSaum@............ Date: Fri, 12 Jan 2001 12:06:56 -0500 I am confused about the relationships between seismic LP filtering, A/D and SPS. Suppose I have an 8 pole bessel filter with a -3 db point of 10 Hz and a 16 bit A/D. Log10(2^16)=4.81, so in power that is 96 db dynamic range. My 8 pole bessel response is down 96 db at about 80 Hz. So I should sample at a minimum of 160 Hz to avoid aliasing that will screw up my lowest bit ? Similarly, for a LP of 1 Hz I should sample at a minimum of 16 SPS? This seems to be a lot higher SPS than most folks are using. Can we assume the seismic spectra naturally falls off at higher frequencies so that we do not have to depend on our LP filter at higher frequencies? Or is my math screwy? Confused, Dave Saum __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LP filters, A/D bits and SPS From: Doug Crice dcrice@............ Date: Fri, 12 Jan 2001 10:05:23 -0800 The short answers are: There are other filters working besides your 8-pole Bessel, like the earth, which is a pretty good low-pass filter. All you really need to filter is the electrical noise and some local cultural noise. I believe your analyis is correct, but assumes that the noise is full scale. A perfect anti-alias filter is just too complex and has too many parts for either amateurs or professionals to build. Compromises happen. To read further, here's a link with a discussion of anti-alias filters in the real world. http://www.chipcenter.com/eexpert/shendrix/shendrix005-2.html Doug Crice David Saum wrote: > > I am confused about the relationships between > seismic LP filtering, A/D and SPS. > > Suppose I have an 8 pole bessel filter > with a -3 db point of 10 Hz and a 16 bit A/D. > > Log10(2^16)=4.81, so in power that is 96 db > dynamic range. > > My 8 pole bessel response is down 96 db > at about 80 Hz. > > So I should sample at a minimum of 160 Hz to > avoid aliasing that will screw up my lowest bit ? > Similarly, for a LP of 1 Hz I should sample at > a minimum of 16 SPS? > > This seems to be a lot higher SPS than most folks > are using. Can we assume the seismic spectra > naturally falls off at higher frequencies so that we > do not have to depend on our LP filter > at higher frequencies? > > Or is my math screwy? > > Confused, > > 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. -- 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: LP filters, A/D bits and SPS From: Karl Cunningham karlc@.......... Date: Fri, 12 Jan 2001 11:33:58 -0800 Hi Dave -- Your math sounds fine to me. But unless you are very close to an earthquake, there isn't going to be much energy at 80Hz. The large dynamic range needed for seismic recording is primarily to accommodate the wide variation in peak amplitudes from seismic signals. 16-bit accuracy is not needed, and really 8 bits of accuracy is more than enough for most purposes. The fact that the lower bits are being affected by aliasing isn't much of a concern if the higher bits are recording good data. Regards, Karl Cunningham At 12:06 PM 1/12/2001 -0500, you wrote: >I am confused about the relationships between >seismic LP filtering, A/D and SPS. > >Suppose I have an 8 pole bessel filter >with a -3 db point of 10 Hz and a 16 bit A/D. > >Log10(2^16)=4.81, so in power that is 96 db >dynamic range. > >My 8 pole bessel response is down 96 db >at about 80 Hz. > >So I should sample at a minimum of 160 Hz to >avoid aliasing that will screw up my lowest bit ? >Similarly, for a LP of 1 Hz I should sample at >a minimum of 16 SPS? > >This seems to be a lot higher SPS than most folks >are using. Can we assume the seismic spectra >naturally falls off at higher frequencies so that we >do not have to depend on our LP filter >at higher frequencies? > >Or is my math screwy? > >Confused, > >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: LP filters, A/D bits and SPS From: barry lotz gbl@....... Date: Fri, 12 Jan 2001 06:17:09 -0800 Hi Dave Sean Thomas had an email awhile back which included an equation for calculating signal amplitude for various magnitude quakes and distances. I believe 16 bit is not unreasonable . Example: at the sensitivity of my sensor magnitude distance count 3.0 250k 150 5.2 250k 32768 5.5 9000k 150 7.7 9000k 32768 winter microseism's na 300 These are approximate values I picked off a log-log graph I plotted. STM had a more extensive table. It is interesting to plot STM's equation and then plot p-p magnitudes that one obtains from ones recorded events. I plotted log distance on the x-axis and log count on the y-axis. Magnitude lines were then plotted in 0.5 intervals. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A/D bits, LP filters From: sean@........... Date: Sat, 13 Jan 2001 03:00:41 -0600 (CST) Regarding the amplitude of seismic waves and digitizer range: I must disagree with Karl when he says 8 bits of accuracy, by which I assume he also means resolution, is sufficient. (Accuracy more properly describes the precision of the reference voltage that determines the value of a bit). Modern seismic studies use the entire content of the waveform for source modeling, tomagraphy, path attenuation, etc, which are dependent on having an un-clipped and un-distorted signal for spectral analysis. A single clipped peak ruins the spectral analysis. Earthquake waveform amplitudes vary logarithmically, and the magnitude scales reflect this. A magnitude M 5 is 100 times more amplitude than a M 3 (everything else being equal). An 8-bit digitizer has a range of 256 counts, 12 bits is 4096, and 16 bits is 65536 counts (or half these values if a bit is used for the sign (+,-). All our newer multichannel broadband stations use 24 bit digitizers which have a range of 16 777 216 counts for a 40 volt p-p signal from sensors with an output of about 2000 volts/meter/second. While we infrequently (like monthly) see amplitudes that actually exceed the 16 bit range, large quakes greater than M 7+ do use much of the dynamic range. I have data from our stations exceeding 2 000 000 counts from South Pacific and Eurasian events. Of course a great quake in the near field of the station would clip the 24 bit system, so most IRIS stations also have a 3 component FBA (Force Balance Accelerometer). The background noise (natural and instrumental) of our stations runs about 200 counts at about -160 db PSD. The least count is 2.384 microvolts. But for my digitizer here at home, I am still using the 12 bit multimeter at 1 sample/second, with a full scale of 200 mv, and a least count of 0.1 mv connected to the STM seis with an output of 1640 v/m/sec. 6-second microseisms run 3 to 15 mv, and it clips on most events greater than M 7.0. And a comment about filters. Doug is quite correct about the natural attenuation of frequencies above a few tens of hz. For all out short period stations (1 hz seismometers) we have a 4-pole Bessel filter in the pre-amp (plus the usual single 30 to 50 hz low pass poles (to reduce amplifying 60 hz noise) that are created by by-passing the high value gain (feedback) Rs with a capacitor, as shown in the pre-amp schematic on my site). After the telemetry (VCO, FM transmitter, FM Receiver, and Discriminator PLL) another 17hz 4-pole filter provides anti-aliasing for the 20 sps digitizer. At my CCM station, the 1 hz high gain system for the CTBT (Comprehensive Test Ban Treaty) uses a 24 hz low pass filter for its 40 sample/sec channels. Although the rules for anti-aliasing are exact, the content of the seismic signal allows some convenient variation; as Doug points out, the actual noise is only a small percentage of the full scale signal. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Strong shock somewhere relatively nearby? From: "meredith lamb" mlamb1@.......... Date: Sat, 13 Jan 2001 10:52:59 -0800 Hi all, Just getting strong P, or whatever waves here in Denver about UTC 17:46... now. Appears to be relatively close by ~ afew hundred or thousand odd miles..... higher frequency, than a distant sample would show. At 17:52, its still short period but strong. Any notes elsewhere? Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong shock somewhere relatively nearby? From: "bobodude" bobodude@............. Date: Sat, 13 Jan 2001 09:59:29 -0800 It very big here on the west coast. ----- Original Message ----- From: meredith lamb To: Sent: Saturday, January 13, 2001 10:52 AM Subject: Strong shock somewhere relatively nearby? > Hi all, > > Just getting strong P, or whatever waves here in Denver about > UTC 17:46... now. Appears to be relatively close by ~ afew > hundred or thousand odd miles..... higher frequency, than a > distant sample would show. At 17:52, its still short period > but strong. > > Any notes elsewhere? > > Meredith Lamb > > > __________________________________________________________ > > 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: Strong shock somewhere relatively nearby? From: "Bryan & Regina Goss" bgoss@.................. Date: Sat, 13 Jan 2001 12:00:44 -0600 I am getting very strong waves here in Mississippi started at 17:40 UTC ----- Original Message ----- From: meredith lamb To: Sent: Saturday, January 13, 2001 12:52 PM Subject: Strong shock somewhere relatively nearby? > Hi all, > > Just getting strong P, or whatever waves here in Denver about > UTC 17:46... now. Appears to be relatively close by ~ afew > hundred or thousand odd miles..... higher frequency, than a > distant sample would show. At 17:52, its still short period > but strong. > > Any notes elsewhere? > > Meredith Lamb > > > __________________________________________________________ > > 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: Strong shock somewhere relatively nearby? From: Angel Rodriguez angel@............ Date: Sat, 13 Jan 2001 13:02:26 -0500 Hello meredith, Saturday, January 13, 2001, 1:52:59 PM, you wrote: ml> Hi all, ml> Just getting strong P, or whatever waves here in Denver about ml> UTC 17:46... now. Appears to be relatively close by ~ afew ml> hundred or thousand odd miles..... higher frequency, than a ml> distant sample would show. At 17:52, its still short period ml> but strong. ml> Any notes elsewhere? ml> Meredith Lamb ml> __________________________________________________________ ml> Public Seismic Network Mailing List (PSN-L) ml> To leave this list email PSN-L-REQUEST@.............. with ml> the body of the message (first line only): unsubscribe ml> See http://www.seismicnet.com/maillist.html for more information. angel here in Panama: I felt this one very strongly. My short periods saturated. I will post soon! -- Best regards, Angel mailto:angel@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A/D bits, LP filters From: Karl Cunningham karlc@.......... Date: Sat, 13 Jan 2001 10:07:49 -0800 Hi Sean-Thomas -- You're right. I didn't mean accuracy. But I'm not sure I really meant resolution either. Perhaps "precision" (or distortion level) might have been a better choice of words. What I was trying to say (and please correct me if I'm wrong) is that it isn't necessary for the system to faithfully record the waveform to within 15ppm (16 bits) for a full-scale signal. For very small signals you want to get as many bits of good data as possible. But if the signal is large, perhaps allowing an imprecision (in other words distortion, including aliases) of something like 8 bits (0.4% of the peak-to-peak signal at the time) may be good enough. Of course, it depends completely on what the data is to be used for. I was suggesting that the compromise of allowing unintentionally aliased out-of-band signals may be ok as long as they are below some fraction of the overall signal level at that time, given the resultant benefit of decreased circuit complexity. Karl At 03:00 1/13/2001 -0600, you wrote: >Regarding the amplitude of seismic waves and digitizer range: > >I must disagree with Karl when he says 8 bits of accuracy, by which I >assume he also means resolution, is sufficient. (Accuracy more properly >describes the precision of the reference voltage that determines the value >of a bit). Modern seismic studies use the entire content of the waveform >for source modeling, tomagraphy, path attenuation, etc, which are dependent >on having an un-clipped and un-distorted signal for spectral analysis. >A single clipped peak ruins the spectral analysis. > >Earthquake waveform amplitudes vary logarithmically, and the magnitude >scales reflect this. A magnitude M 5 is 100 times more amplitude than a >M 3 (everything else being equal). An 8-bit digitizer has a range of >256 counts, 12 bits is 4096, and 16 bits is 65536 counts (or half these >values if a bit is used for the sign (+,-). All our newer multichannel >broadband stations use 24 bit digitizers which have a range of 16 777 216 >counts for a 40 volt p-p signal from sensors with an output of about >2000 volts/meter/second. While we infrequently (like monthly) see amplitudes >that actually exceed the 16 bit range, large quakes greater than M 7+ do >use much of the dynamic range. I have data from our stations exceeding >2 000 000 counts from South Pacific and Eurasian events. Of course a great >quake in the near field of the station would clip the 24 bit system, so most >IRIS stations also have a 3 component FBA (Force Balance Accelerometer). >The background noise (natural and instrumental) of our stations runs >about 200 counts at about -160 db PSD. The least count is 2.384 microvolts. > >But for my digitizer here at home, I am still using the 12 bit multimeter >at 1 sample/second, with a full scale of 200 mv, and a least count of >0.1 mv connected to the STM seis with an output of 1640 v/m/sec. 6-second >microseisms run 3 to 15 mv, and it clips on most events greater than M 7.0. > > >And a comment about filters. Doug is quite correct about the natural >attenuation of frequencies above a few tens of hz. For all out short >period stations (1 hz seismometers) we have a 4-pole Bessel filter in >the pre-amp (plus the usual single 30 to 50 hz low pass poles (to reduce >amplifying 60 hz noise) that are created by by-passing the high value gain >(feedback) Rs with a capacitor, as shown in the pre-amp schematic on my site). >After the telemetry (VCO, FM transmitter, FM Receiver, and Discriminator PLL) >another 17hz 4-pole filter provides anti-aliasing for the 20 sps digitizer. >At my CCM station, the 1 hz high gain system for the CTBT (Comprehensive >Test Ban Treaty) uses a 24 hz low pass filter for its 40 sample/sec channels. >Although the rules for anti-aliasing are exact, the content of the seismic >signal allows some convenient variation; as Doug points out, the actual >noise is only a small percentage of the full scale signal. > >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: Re: Strong shock somewhere relatively nearby? From: barry lotz gbl@....... Date: Fri, 12 Jan 2001 22:11:44 -0800 Hi all From the USGS helicorder it appears to be coming from South or central america area since Galapagos is the first to receive and New mexico second. Regards Barry meredith lamb wrote: > Hi all, > > Just getting strong P, or whatever waves here in Denver about > UTC 17:46... now. Appears to be relatively close by ~ afew > hundred or thousand odd miles..... higher frequency, than a > distant sample would show. At 17:52, its still short period > but strong. > > Any notes elsewhere? > > Meredith Lamb > > __________________________________________________________ > > 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: R: Strong shock somewhere relatively nearby? From: "Francesco" franuc@...... Date: Sat, 13 Jan 2001 19:12:33 +0100 CENTRAL AMERICA? GOOD TRACES FROM ITALY SOME AGENCIES LOCATED IT HONDURAS/MEXICO I've posted the first vawes (P) of the italian station CASTELLUCCIO (2100 mt o.l.s.) onto psn-event list Ms 6.6? Francesco, Italy ----- Original Message ----- From: bobodude To: Sent: Saturday, January 13, 2001 6:59 PM Subject: Re: Strong shock somewhere relatively nearby? > It very big here on the west coast. > > ----- Original Message ----- > From: meredith lamb > To: > Sent: Saturday, January 13, 2001 10:52 AM > Subject: Strong shock somewhere relatively nearby? > > > > Hi all, > > > > Just getting strong P, or whatever waves here in Denver about > > UTC 17:46... now. Appears to be relatively close by ~ afew > > hundred or thousand odd miles..... higher frequency, than a > > distant sample would show. At 17:52, its still short period > > but strong. > > > > Any notes elsewhere? > > > > Meredith Lamb > > > > > > __________________________________________________________ > > > > 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. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: I: EQ Alert 13Jan2001 17:33 From: "Francesco" franuc@...... Date: Sat, 13 Jan 2001 19:18:42 +0100 this is the first alarm message by PUMA Bye Francesco Italy > *********************** Earthquake Notification Message *********************** > > EARTHQUAKE PARAMETERS DETERMINED BY DIFFERENT AGENCIES/METHODS: > > > D a t e Time (UTC) Location Dep Magn. T AGY R e g i o n HHMM > > 13Jan2001 17:33:22.0 12.0N 90.6W 33 mb=6.2 A*NOR OFF COAST OF CENTRAL AMER1755 > 13Jan2001 17:34:03.0 13.0N 88.0W 33 mb=6.3 A*YKA EL SALVADOR 1754 > > Radius: 151 km > **************************************************************************** *** > This is a fully automatic EARTHQUAKE NOTIFICATION MESSAGE > compiled by the Swiss Seismological Service, Zurich, Switzerland. > It was generated according to your subscription to messages based on > - for more information please contact: > - on WWW: http://seismo.ethz.ch/redpuma/redpuma.html > - via E-Mail: kradolfer@.................. > Message generation time: Jan 13 17:55:21 2001 UTC > > Legend: > > T : Location Type (A: Automatic, less reliable; M: Manual, more reliable) > AGY : Agency reporting location: > SED : Swiss Seismological Service GER : GERESS array, Germany > NEI : NEIC, USGS, Golden, CO, U.S.A. NOR : NORSAR Array, Norway > YKA : Yellowknife Array, Canada ING : I.N.G., Rome, Italy > MAD : I.G.N., Madrid, Spain IDC : GSE-IDC, Washington > LED : Geol. Survey B-W,Freiburg,Germany THE : Thessaloniki, Greece > EMS : EMSC/CSEM (LDG/ING/IGN) JPN : JWA, Tokyo, Japan > LDG : LDG, Paris ISR : IPRG,Tel Aviv,Israel > MPK : USGS Menlo Park, U.S.A. BGR : SDAC, Hannover,Germany > ROM : NIEP, Bucharest, Romania GSR : GS RAS, Obninsk, Russia > HHMM : Hour and Minute (UTC) when message arrived in Zurich > Radius: Radius of smallest circle circumscribing all locations marked with * > (this is a measure of the scatter of the locations) > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I: EQ Alert 13Jan2001 17:33-7.6 From: Canie canie@........... Date: Sat, 13 Jan 2001 10:35:36 -0800 Its listed at NEIC: 01/01/13 17:33:31 12.77N 88.83W 60.0 7.6Mw B OFF COAST OF CENTRAL AMERICA Canie At 07:18 PM 1/13/01 +0100, Francesco wrote: >this is the first alarm message by PUMA > >Bye >Francesco Italy > > > > > *********************** Earthquake Notification Message >*********************** > > > > EARTHQUAKE PARAMETERS DETERMINED BY DIFFERENT AGENCIES/METHODS: > > > > > > D a t e Time (UTC) Location Dep Magn. T AGY R e g i o n >HHMM > > > > 13Jan2001 17:33:22.0 12.0N 90.6W 33 mb=6.2 A*NOR OFF COAST OF CENTRAL >AMER1755 > > 13Jan2001 17:34:03.0 13.0N 88.0W 33 mb=6.3 A*YKA EL SALVADOR >1754 > > > > Radius: 151 km > > >**************************************************************************** >*** > > This is a fully automatic EARTHQUAKE NOTIFICATION MESSAGE > > compiled by the Swiss Seismological Service, Zurich, Switzerland. > > It was generated according to your subscription to messages based on > > - for more information please contact: > > - on WWW: http://seismo.ethz.ch/redpuma/redpuma.html > > - via E-Mail: kradolfer@.................. > > Message generation time: Jan 13 17:55:21 2001 UTC > > > > Legend: > > > > T : Location Type (A: Automatic, less reliable; M: Manual, more >reliable) > > AGY : Agency reporting location: > > SED : Swiss Seismological Service GER : GERESS array, >Germany > > NEI : NEIC, USGS, Golden, CO, U.S.A. NOR : NORSAR Array, >Norway > > YKA : Yellowknife Array, Canada ING : I.N.G., Rome, >Italy > > MAD : I.G.N., Madrid, Spain IDC : GSE-IDC, >Washington > > LED : Geol. Survey B-W,Freiburg,Germany THE : Thessaloniki, >Greece > > EMS : EMSC/CSEM (LDG/ING/IGN) JPN : JWA, Tokyo, Japan > > LDG : LDG, Paris ISR : IPRG,Tel >Aviv,Israel > > MPK : USGS Menlo Park, U.S.A. BGR : SDAC, >Hannover,Germany > > ROM : NIEP, Bucharest, Romania GSR : GS RAS, Obninsk, >Russia > > HHMM : Hour and Minute (UTC) when message arrived in Zurich > > Radius: Radius of smallest circle circumscribing all locations marked with >* > > (this is a measure of the scatter of the locations) > > > > > >__________________________________________________________ > >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: A/D bits, LP filters From: barry lotz gbl@....... Date: Fri, 12 Jan 2001 22:38:11 -0800 Hi Karl I look at the 16 bit digitizer as an alternate to a autogain system. I tried autogain changing during events and the bookkeeping became a problem as did the slight zero shifts during gain changes. I would like to record both local and distant signals and seem to use most of the 16 bits . The smallest event p-p I recorded recently is about 500. With a use of 10% of this for minimum signal it would be around 50. I have been wanting to lower my gain a little recently. Looks like with todays event down south I may clip again. Regards Barry Karl Cunningham wrote: > Hi Sean-Thomas -- > > You're right. I didn't mean accuracy. But I'm not sure I really meant > resolution either. Perhaps "precision" (or distortion level) might have > been a better choice of words. > > What I was trying to say (and please correct me if I'm wrong) is that it > isn't necessary for the system to faithfully record the waveform to within > 15ppm (16 bits) for a full-scale signal. For very small signals you want > to get as many bits of good data as possible. But if the signal is large, > perhaps allowing an imprecision (in other words distortion, including > aliases) of something like 8 bits (0.4% of the peak-to-peak signal at the > time) may be good enough. Of course, it depends completely on what the > data is to be used for. > > I was suggesting that the compromise of allowing unintentionally aliased > out-of-band signals may be ok as long as they are below some fraction of > the overall signal level at that time, given the resultant benefit of > decreased circuit complexity. > > Karl > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: PSE POST TO PSN] From: barry lotz gbl@....... Date: Fri, 12 Jan 2001 22:55:31 -0800 I can not deliver my msg to the list, can you pse post it there? A 32 seconds seism (5.8), was felt here at 17:34 UT, causing alarm to locals, located 75 miles SE Guatemala City, in front of El Salvador Coast. Rolando Benitez Guatemala City Subject: RE: Strong shock somewhere relatively nearby? From: "Kareem" kareemjupiter@............. Date: Sat, 13 Jan 2001 13:02:40 -0800 Barry, Where are you seeing the USGS helicorders? No visible traces of the event on my PS2 system - It's vertical and set very low (boohoo). -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of barry lotz Sent: Friday, January 12, 2001 10:12 PM To: psn-l@.............. Subject: Re: Strong shock somewhere relatively nearby? Hi all From the USGS helicorder it appears to be coming from South or central america area since Galapagos is the first to receive and New mexico second. Regards Barry meredith lamb wrote: > Hi all, > > Just getting strong P, or whatever waves here in Denver about > UTC 17:46... now. Appears to be relatively close by ~ afew > hundred or thousand odd miles..... higher frequency, than a > distant sample would show. At 17:52, its still short period > but strong. > > Any notes elsewhere? > > Meredith Lamb > > __________________________________________________________ > > 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: earthquake realtime chat in a "just shaken" area... From: "Kareem" kareemjupiter@............. Date: Sat, 13 Jan 2001 13:41:24 -0800 Does anyone know of any realtime chat services in the area of central america which may be dicussing the latest in terms of damage reports, experiences, with the latest earthquake? (For that matter, any chat services involving a group of seism-interested folks?) It would be interesting to be able to monitor a particular area after such a significant quake. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong shock somewhere relatively nearby? From: Michael Tolchard michael@............. Date: Sat, 13 Jan 2001 18:41:27 -0800 Just had a 4.3 in L.A. Area ..... At 10:52 AM 1/13/01 -0800, you wrote: >Hi all, > >Just getting strong P, or whatever waves here in Denver about >UTC 17:46... now. Appears to be relatively close by ~ afew >hundred or thousand odd miles..... higher frequency, than a >distant sample would show. At 17:52, its still short period >but strong. > >Any notes elsewhere? > >Meredith Lamb > > >__________________________________________________________ > >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: Strong shock somewhere relatively nearby? From: "I.ES.N." info@........ Date: Sun, 14 Jan 2001 04:14:08 +0100 Hi gang this is the first report on web 02:26:15.4 34.1N 118.6W Mb6.1 A NEIA SOUTHERN CALIFORNIA It's wright? Francesco Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong shock somewhere relatively nearby? From: Canie canie@........... Date: Sat, 13 Jan 2001 19:37:31 -0800 At 04:14 AM 1/14/01 +0100, you wrote: >Hi gang > >this is the first report on web > >02:26:15.4 34.1N 118.6W Mb6.1 A NEIA SOUTHERN CALIFORNIA > >It's wright? No - its wrong - 1 4.3 at 6:26pm pst followed by a 4.1 at 6:50pm - I hope these aren't foreshocks to something bigger! I'm in Long Beach and we did not feel them here but they were felt in Santa Monica area. Canie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: E-Bay possible small seismo base plate From: "meredith lamb" mlamb1@.......... Date: Sat, 13 Jan 2001 21:02:45 -0800 Hi all, Ran across one particular E-Bay item/s which could provide a excellent small seismo base plate; i.e., a S-G, or small boom length horizontal/vertical home brew configuration, or, whatever one can configure on the home front for the size offered. The auction ends January 20th. The seller appears to have a excellent feedback on some 7,000 odd items sold in the past. If one is into tools, misc electrical whatever, be sure to check "view sellers other auctions" which has literally hundred of items listed. The beginning bid (none yet) is $13.99. Stuff like this is very rare. Go to: http://www.ebay.com/index.html They are 1.25" Thick, 7.25" wide and 13.375" length. They appear to have been machine sawed rectangular blocks and look relatively squared. The thickness sure won't allow much bending under load, or any mass wandering tilt influence! Item #'s = 541796378, 541796837, 541797076, 541797319, 541797555, 541797830, 541798213, 541798490, 541798776, 541799069. The seller also has a more private auction site, which appears to offer another 10 of these plates at $14.99 beginning bid, but one would have to register and do whatever the requirements are with that web site. No bids yet, and that ends Jan 19th. http://www.reliableiam.com/cgi-bin/auctioneer.exe?action=list&category=110010 The home beginning page is: http://www.reliabletools.com This seller is in Irwindale, California, U.S.A. Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: small seismograph From: "Ed Ianni" edwianni@........ Date: Sun, 14 Jan 2001 11:54:53 -0500 Does anyone have specifications for the mini mini seismograph? Thank you. Ed.
Does anyone have specifications = for the mini=20 mini seismograph?
Thank you. = Ed.
Subject: Re: small seismograph From: "Frank Cooper" fxc@....... Date: Sun, 14 Jan 2001 13:56:49 -0600 Hi Ed, Email John Cole of Pearland, Texas, USA, for information as he is the = originator of the mini mini. Note that I have sent a copy of this email = to John. You can see the mini mini on his web page at: = http://freeweb.pdq.net/four.htm Frank Cooper, Friendswood, Texas, USA ----- Original Message -----=20 From: Ed Ianni=20 To: psn-l@................. Sent: Sunday, January 14, 2001 10:54 AM Subject: small seismograph Does anyone have specifications for the mini mini seismograph? Thank you. Ed.
Hi Ed,
Email John Cole of Pearland, Texas, USA, for = information as he=20 is the originator of the mini mini.  Note that I have sent a copy = of this=20 email to John.  You can see the mini mini on his web page at:  = http://freeweb.pdq.net/four.htm<= /A>
Frank Cooper, Friendswood, Texas, USA
----- Original Message -----
From:=20 Ed = Ianni
Sent: Sunday, January 14, 2001 = 10:54=20 AM
Subject: small = seismograph

Does anyone have specifications = for the mini=20 mini seismograph?
Thank you.=20 Ed.
Subject: Re: small seismograph From: "Frank Cooper" fxc@....... Date: Sun, 14 Jan 2001 14:01:06 -0600 Hi Ed, Sorry I did not give the complete url for John Cole's web page. It can = be found at: http://freeweb.pdq.net/fxc/four.htm Frank Cooper, Friendswood, Texas, USA ----- Original Message -----=20 From: Ed Ianni=20 To: psn-l@................. Sent: Sunday, January 14, 2001 10:54 AM Subject: small seismograph Does anyone have specifications for the mini mini seismograph? Thank you. Ed.
Hi Ed,
Sorry I did not give the complete url for John = Cole's web=20 page.  It can be found at:  http://freeweb.pdq.net/fxc/f= our.htm
Frank Cooper, Friendswood, Texas, USA
----- Original Message -----
From:=20 Ed = Ianni
Sent: Sunday, January 14, 2001 = 10:54=20 AM
Subject: small = seismograph

Does anyone have specifications = for the mini=20 mini seismograph?
Thank you.=20 Ed.
Subject: Small and yet smaller Seismographs From: "Danie Overbeek" danieo@............ Date: Mon, 15 Jan 2001 11:04:47 +0000 Hi I don't know what a mini-mini seismograph is but it cannot be smaller than the Wood-Anderson torsional seismometer which has a horizontal pendulum all of 6 millimetres long. The instrument was sold in kit form by the Sprengnether Instrument Company of St Louis. It was designed to record a trace on a drum wrapped in photographic paper but one could substitute an electronic optical transducer for the drum. See "The Amateur Scientist" by CL Stong, Heinemann, 1962, page 229. This is the book which started me off on seismography. If you cannot access the book then I'll be happy to quote a few paragraphs for psn. Cheers all Danie Overbeek. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: D Collins dcollin@........... Date: Mon, 15 Jan 2001 06:41:40 -0700 At 04:04 AM 1/15/01 , you wrote: >Hi > >I don't know what a mini-mini seismograph is but it cannot be >smaller than the Wood-Anderson torsional seismometer which has >a horizontal pendulum all of 6 millimetres long. The instrument >was sold in kit form by the Sprengnether Instrument Company of >St Louis. It was designed to record a trace on a drum wrapped >in photographic paper but one could substitute an electronic >optical transducer for the drum. See "The Amateur Scientist" >by CL Stong, Heinemann, 1962, page 229. This is the book >which started me off on seismography. If you cannot access >the book then I'll be happy to quote a few paragraphs for psn. > >Cheers all > >Danie Overbeek. THAT book started a lot of us on the path we are on now. Darrell __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: Thomas W Leiper twleiper@........ Date: Mon, 15 Jan 2001 10:06:25 -0500 On Mon, 15 Jan 2001 06:41:40 -0700 D Collins writes: > At 04:04 AM 1/15/01 , you wrote: > [edited] > > >This is the book which started me off on seismography. > > > >Cheers all > > > >Danie Overbeek. > > > THAT book started a lot of us on the path we are on now. > > Darrell > Yes, and that path must end in destruction, just as it was inevitable that Quint would be eaten by the shark that he pursued all his life, we will all probably be swallowed up by some fissure or incinerated in a lava flow. Goodby cruel world!! __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: "Ian Greenwood" judgedred@.............. Date: Mon, 15 Jan 2001 21:00:40 -0000 Subject: Small and yet smaller Seismographs > Hi See "The Amateur Scientist" > by CL Stong, Heinemann, 1962, page 229. This is the book > which started me off on seismography. If you cannot access > the book then I'll be happy to quote a few paragraphs for psn. > > Cheers all > > Danie Overbeek. Danie, A few paragraphs would be much appreciated!!! Thanks Ian __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: "Ian Greenwood" judgedred@.............. Date: Mon, 15 Jan 2001 21:04:06 -0000 "The Amateur Scientist" > >by CL Stong, Heinemann, 1962, page 229. This is the book > >which started me off on seismography. If you cannot access > >the book then I'll be happy to quote a few paragraphs for psn. > > > >Cheers all > > > >Danie Overbeek. > > > THAT book started a lot of us on the path we are on now. > > Darrell Good, because that book got the group going that got me started!!! Tectonic motion in action! Ian __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: "Ian Greenwood" judgedred@.............. Date: Mon, 15 Jan 2001 21:05:35 -0000 > Yes, and that path must end in destruction, just as it was > inevitable that Quint would be eaten by the shark that he > pursued all his life, we will all probably be swallowed up > by some fissure or incinerated in a lava flow. > > Goodby cruel world!! Public peSeismistic Network, or what? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Cruel world and Wood-Andersons From: sean@........... Date: Mon, 15 Jan 2001 15:37:11 -0600 (CST) Thomas, Darrell, Danie, Re: "Goodbye cruel ..."; of course we all know that seismographs attract earthquakes like lightning rods, so your chance of your wallet being swallowed by a fissure increases exponentially with your success at amateur seismology. (I have actually encountered this quake attraction thinking in trying to permit telemetry station sites in the Ozarks.) Regarding the Wood-Anderson torsional seismometer: I have operated several versions of this, including the original wooden box designs and the later compact refinements by Q.E.D. Early instruments were set to modest periods, with 2.7 seconds being common, but relatively unstable. Later a standard of 0.8 seconds and a magnification of 2800 was agreed on for a standard 60mm/min photographic record. Because its magnification is so low, real data was a rarity unless you were close to an active fault zone. But for larger quakes it was very useful for calculating the Richter magnitude, which was based on the instrument. Since they were horizontal sensors, we photo-recorded them on a triple- record drum along with a high gain 1 second vertical seismometer/galvanometer system. But photo-recording became costly and was complicated and relatively time consuming, so currently the W-As are adornments in a display case, and the W-A response can be derived from any broadband signal and scaled to any near-field magnitude. The original article by Anderson and Wood was published in the BSSA, vol 15, pp 1072, in 1925. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small and yet smaller Seismographs From: "Ted Blank" ted@.......... Date: Mon, 15 Jan 2001 17:13:45 -0500 I have seen the C. L. Stong book in the library, it is wonderful and covers an enormous range of interests. My interest started from the Lehman article in 1979. When we get to predicting quakes, maybe we should call ourselves the Public Psi-smic Network... The masked appender __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cruel world and Wood-Andersons From: John Hernlund hernlund@............ Date: Mon, 15 Jan 2001 15:03:19 -0800 sean@........... wrote: > Re: "Goodbye cruel ..."; of course we all know that seismographs attract > earthquakes like lightning rods, so your chance of your wallet being > swallowed by a fissure increases exponentially with your success at > amateur seismology. (I have actually encountered this quake attraction > thinking in trying to permit telemetry station sites in the Ozarks.) I have talked to my apartment manager in Santa Monica about setting up a seismograph (because it would require minor alteration of their property) and he said it would be great. He did, however, want some assurance that the thing wouldn't attract earthquakes! John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong shock somewhere relatively nearby? From: John Hernlund hernlund@............ Date: Mon, 15 Jan 2001 15:12:10 -0800 Canie wrote: > No - its wrong - 1 4.3 at 6:26pm pst followed by a 4.1 at 6:50pm - I hope > these aren't foreshocks to something bigger! > > I'm in Long Beach and we did not feel them here but they were felt in Santa > Monica area. We didn't feel anything in Santa Monica...nor did our neighbors. The weird thing is that the Northridge quake sent strong energy into Santa Monica through what some people think is a lens-like structure under the Santa Monica Mountains. This quake looked close to Northridge, but no focusing of energy apparently occurred here this time. But, due to this proximity, I would guess that this may be some type of after affect of the Northridge quake rather that a foreshock....but I am not sure. John Hernlund Department of Earth and Space Sciences University of California, Los Angeles hernlund@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cruel world and Wood-Andersons From: "Ted Blank" ted@.......... Date: Mon, 15 Jan 2001 18:30:56 -0500 Attract quakes? Just the opposite, tell him the best way to insure there won't be any quakes anywhere near him will be to let you set up the seismometer and keep it working. Anybody on this list knows quakes only happen when your station is down. Of course if the disk fills up or the ink runs dry, head for the hills, there's a quake on the way. Regards, Ted Blank __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cruel world and Wood-Andersons From: macsmith macsmith@......... Date: Mon, 15 Jan 2001 15:15:53 -1000 when I used to run my machine with Microsoft Windows, it crashed often and there were frequent and co-incident local quakes. Since I converted to Linux there have been very few crashes or quakes! Perhaps everyone in psn should try Linux, it might make the world safer! ;-) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cruel world and Wood-Andersons From: bc bruce@....... Date: Mon, 15 Jan 2001 20:26:03 -0500 Gosh, I wonder what would happen if you installed a seismometer in a trailer park? We could take up a pool to see which came first, the funnel or the quake. Bruce At 03:03 PM 01/15/2001 -0800, you wrote: >sean@........... wrote: > > > Re: "Goodbye cruel ..."; of course we all know that seismographs attract > > earthquakes like lightning rods, so your chance of your wallet being > > swallowed by a fissure increases exponentially with your success at > > amateur seismology. (I have actually encountered this quake attraction > > thinking in trying to permit telemetry station sites in the Ozarks.) > >I have talked to my apartment manager in Santa Monica about setting up >a seismograph (because it would require minor alteration of their >property) and he said it would be great. He did, however, want some >assurance that the thing wouldn't attract earthquakes! > > >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. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: station failures and quakes From: sean@........... Date: Mon, 15 Jan 2001 20:48:29 -0600 (CST) Ted, I agree from years of experience that "Mother knows" when a network is crippled, and that redundant systems secretly coordinate their failures. Only in the Aleutian network did we find that activity did not decrease after the summer maintenance and refurbishment effort, probably because we usually had 10 to 20 quakes per day. I had also interleaved the telemetry, microfilm, and tape channels to frustrate "Mother" so that a 50% channel loss would still leave us with 100% of the area coverage. If nothing else goes wrong, the best trained human will destroy the data, often because they are the most important scientist and not the guy who routinely handles the data, so they make a backup of the data on a non- existent server, ignore the complaints (they KNOW they are right) and then trash the original data by some very clever stupidity. Even in the days of photo-recording, the top geophysicist walked up the street to recover the records of the Good Friday Alaskan quake from the station under the gym, and on the way back to our processing darkroom, let the lid fall off the light-tight photo-record container. The press was all over the place, but all we had was very black records! There is more to the Ozark network story. We were doing a pre-impoundment study for a C.O.E. planned dam on the Meremac river that the voters finally killed (which was even more of a plus because the dam would have flooded the caverns where my CCM station now is.) We always try to get the interest and enthusiasm of our property owners in permitting station sites. But the scientific value of out study (we didn't openly connect it to the dam project) seems to have been lost on some of the locals in this area of dirt roads and hardwood forests. We had a few yagi antennas stolen because they looked like TV antennas, and we did recover one from the top of a house trailer. But when we went to remove the network, one station was completely missing, so we went to the landowners' cabin. It was all there on his porch; he claimed that he thought we had lost it. But when I went to pick it up, he stepped in and said it was his, and I would have to pay him a finders' fee. He wanted $100, but all I had was about $40, so he took it. After I loaded the equipment, I told him that if I had any problems with any other stations in the area, I would burn his cabin down, which is the ultimate threat in a feud in those parts. I know that the old boys in the area communicated fairly well, so we didn't have any further problems. At the time we were planning on re-occupying the same sites for post impoundment seismicity studies. We had a similar problem in Tadjikistan, were anything scientific "like" was associated with less-than-popular Moscow by the nomadic horsemen, who liked to lasso the yagi antenna (on a 3 m pipe mast) and drag it down. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: station failures and quakes From: BOB BARNS roybar@........ Date: Tue, 16 Jan 2001 10:18:54 -0500 Sean-Thomas-- Thanks for the interesting stories. You should consider writing a book about your experiences. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 2 ebay items From: BOB BARNS roybar@........ Date: Tue, 16 Jan 2001 10:40:15 -0500 Hi gang, Ebay #542852319 is a "Taylor Instrument Seismometer". I have no idea what this is but the starting price is $10 and the auction ends 1/21. Ebay # 1404463168 is a book "Seismology & Plate Tectonics" by Gubbins, 1992 339 pages. The starting price is $15 and the auction ends 1/25. Bob Barns __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 2 ebay items From: Doug Crice dcrice@............ Date: Tue, 16 Jan 2001 07:46:06 -0800 I monitor e-bay for seismographs. Approximately 90% of devices alleged to be "seismographs" (including this one) turn out to be meteorological recording instruments. Another 8% are chart recorders. It seems that the general public thinks anything with a chart recorder is a seismograph. Doug Crice BOB BARNS wrote: > > Hi gang, > Ebay #542852319 is a "Taylor Instrument Seismometer". I have no idea > what this is but the starting price is $10 and the auction ends 1/21. > Ebay # 1404463168 is a book "Seismology & Plate Tectonics" by Gubbins, > 1992 339 pages. The starting price is $15 and the auction ends 1/25. > 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. -- 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: 2 ebay items From: "John Tacinelli" John.Tacinelli@........ Date: Tue, 16 Jan 2001 10:15:06 -0600 I think that "seismograph" is a barograph for recording barometric = pressure. It has nothing to do with seismology. John Tacinelli Earth Science Instructor Rochester Community and Technical College __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: missing instructions From: "Ed Ianni" edwianni@........ Date: Wed, 17 Jan 2001 22:03:37 -0500 Would anyone out there know where I could get the instructions for a = "Perkin Elmer r 100 a" chart recorder? Thanks, Ed.
Would anyone out there know where I = could get the=20 instructions for a "Perkin Elmer r 100 a" chart recorder? Thanks,=20 Ed.
Subject: From: DMo6117771@....... Date: Thu, 18 Jan 2001 22:48:13 EST i am trying to use a geospace geophone to close set of contacts that initiates a radio transmission to a remote reciever. this thing needs to be adjustable in sensitivity or amplification in order for human footsteps to be the minimum neccessary to activate the contact closure. it must be dc in order to be used in the backwoods. any help or info would be greatly appreciated. Thanks, David __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: backwoods geophone From: "David Saum" DSaum@............ Date: Fri, 19 Jan 2001 08:36:24 -0500 > From: DMo6117771@....... > Date: Thu, 18 Jan 2001 22:48:13 EST > > i am trying to use a geospace geophone to close set of contacts that > initiates a radio transmission to a remote reciever. this thing needs to be > adjustable in sensitivity or amplification in order for human footsteps to be > the minimum neccessary to activate the contact closure. it must be dc in > order to be used in the backwoods. any help or info would be greatly > appreciated. So you want to detect people, but not quakes? Most of us have spent a lot of time designing our semismometers to do just the opposite! Sounds like a project I heard about during the Viet Nam war. It was a remote sensor that could be dropped on the Ho Chi Min trail and report back when people or vehicles came near. I may have some electronics that could be modified to solve your problem. I am working on an inexpensive seismic circuit (amp/filter/adc) that can run off a 9v battery. It is controlled by a PIC microprocessor that can do other processing. It draws less than 4.5ma, so a 9v nicad battery would last about 100 hours. Ciao, Dave > > Thanks, > David __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Footstep Detector From: Karl Cunningham karlc@.......... Date: Fri, 19 Jan 2001 13:51:56 -0800 Gateway Electronics has a $10 kit including a geophone and adjustable threshold detector that flashes an LED when it detects vibration. Using a relay instead of the LED, I think it would probably work for what you are doing. Their website is at http://www.gatewayelex.com I didn't see it on their website but I saw them in their store yesterday. Perhaps an email to them would do the trick. Regards, Karl At 10:48 PM 1/18/2001 EST, you wrote: >i am trying to use a geospace geophone to close set of contacts that >initiates a radio transmission to a remote reciever. this thing needs to be >adjustable in sensitivity or amplification in order for human footsteps to be >the minimum neccessary to activate the contact closure. it must be dc in >order to be used in the backwoods. any help or info would be greatly >appreciated. > >Thanks, >David >__________________________________________________________ > >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: Footstep Detector From: "Ian Greenwood" judgedred@.............. Date: Fri, 19 Jan 2001 22:28:49 -0000 http://www.gatewayelex.com/gadgets.htm will get the page Subject: Re: Footstep Detector __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SDR Files to Audio (Wav) program From: Arie Verveer ajbv@............ Date: Sat, 20 Jan 2001 20:19:17 +0800 Hi, I have just, completed an upgrade to the program "SdrDrum". It now can generate audio (.wav) files with the ".GIF", heiplot image. If the user so requests. If you are interested please read the upgraded instructions and the program can be found at: (Click "Download PSN related Software" at the bottom of the page) http://www.iinet.net.au/~ajbv/ There is an amazing richness in sounds, from a thunder of a quake to the pop of the seismic waves bouncing from the core. The magnetic field has sounds resembling bird calls. Cheers Arie PS: read the instructions first. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: What Do you think From: "Bryan & Regina Goss" bgoss@.................. Date: Sun, 21 Jan 2001 19:18:33 -0600 Well I finally got my sight updated tell me what you all think. Just wandering if anyone else had used a Plexiglas box for a cover...... http://www.freedom2000net.com/userpages/bgoss/seis/index.htm
Well I finally got my sight updated = tell me what=20 you all think.
Just wandering if anyone else had used = a Plexiglas=20 box for a cover......
 
htt= p://www.freedom2000net.com/userpages/bgoss/seis/index.htm Subject: Re: What Do you think From: Angel Rodriguez angel@............ Date: Mon, 22 Jan 2001 17:09:33 -0500 Hello Bryan, Sunday, January 21, 2001, 8:18:33 PM, you wrote: BRG> Well I finally got my sight updated tell me what you all think. BRG> Just wandering if anyone else had used a Plexiglas box for a cover...... BRG> http://www.freedom2000net.com/userpages/bgoss/seis/index.htm Hi Bryan, I think you seismogaph looks great!! And the gif of the quake you got looks great too. Nice work!! -- Best regards, Angel mailto:angel@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ebay item...... ending an. 26th From: "Ed Ianni" edwianni@........ Date: Mon, 22 Jan 2001 18:34:27 -0500 There is a "dutch" auction on ebay for "earthquake = alarms".????????......... Item # 545650690.
There is a "dutch" auction on ebay for = "earthquake=20 alarms".????????......... Item # 545650690.
Subject: Re: What Do you think From: barry lotz gbl@....... Date: Mon, 22 Jan 2001 06:07:20 -0800 Hi Brian I like your photos also . One of these days I hope to share also. I currently use plexiglas for my lehman also. It has works well for me. I was previously getting condensation in the winter due to moisture coming thru my garage slab. I put a layer of plastic drop cloth under (the thinist I could find (0.5 mil)). It solved that problem. I also put a strip of weather stripping(sticky on one side) under the where the plastic contacts the concrete to help with slab irregularities.Looks like you have a slightly different arrangement which probably works as well. I am still concerned about the lack of emi shielding of my use of a plastic cover, but possibly the low pass filters take care of most of this ,since we look at very low(relatively speaking)frequencies. I have blown a few opamps due to lightning. I haven't incorporated circuit overloads for this problem yet. Regards Barry Bryan & Regina Goss wrote: > Well I finally got my sight updated tell me what you all think.Just > wandering if anyone else had used a Plexiglas box for a > cover...... http://www.freedom2000net.com/userpages/bgoss/seis/index.htm Hi Brian
   I like your photos also . One of these days I hope to share also. I currently use plexiglas for my lehman also. It has works well for me. I was previously getting condensation in the winter due to moisture coming thru my garage slab. I put a layer of plastic drop cloth under (the thinist I could find (0.5 mil)). It solved that  problem. I also put a strip of weather stripping(sticky on one side) under the where the plastic contacts the concrete to help with slab irregularities.Looks like you have a slightly different arrangement which probably works as well. I am still concerned about the lack of emi shielding of my use of a  plastic cover, but possibly the low pass filters take care of most of this ,since we look at very low(relatively speaking)frequencies. I have blown a few opamps due to lightning. I haven't incorporated circuit overloads for this problem yet.
Regards
Barry

Bryan & Regina Goss wrote:

Well I finally got my sight updated tell me what you all think.Just wandering if anyone else had used a Plexiglas box for a cover...... http://www.freedom2000net.com/userpages/bgoss/seis/index.htm
Subject: Re: What Do you think From: ChrisAtUpw@....... Date: Mon, 22 Jan 2001 22:36:41 EST In a message dated 22/01/01, bgoss@.................. writes: > Well I finally got my sight updated tell me what you all think. The results look OK, which is what counts. I see that you have used both magnetic and fluid damping. With the magnetic damping, you have used Al plate which is not nearly as effective as Cu and you have also used a very large magnetic gap. This suggests that your magnetic damping is a sort of 'add on' correction. The problem with fluid damping in general is the huge changes in fluid viscosity with temperature, particularly between summer and winter. If it works OK, don't 'fix' it. If you want to experiment at any time, I suggest you try a bit of 1/8" Copper plate, no fluid and reduce the magnet gap till you get ~critical damping. This will be independent of temperature. You might want at some stage to fit a small underrun lamp (1/2 to 2/3 rated voltage) inside the top of the box to give a stable temperature gradient to the internal air. A layer or two of bubble wrap with suitable viewing holes cut in it could provide additional insulation while still allowing light through. A layer of polythene damp proof sheeting under the whole apparatus could prevent any condensation problems from the flooring. If you get any problems with lightning where you are, you might consider mounting the amplifier on the baseplate and connecting the baseplates together with a common earth. For others still in the design stage, you can get threaded Brass and Stainless Steel rods, which are both non magnetic and so won't give problems with magnetic interactions. Another alternative is to get plain rod and have some thread put one end. Mounting the sensor system just inboard of the weight can give a more compact system. Socket cap screws can make levelling adjustments easier to perform and fine threads are available - it is a bit easier to get an extension rod into a hole than a flat screwdriver bit into a slot. What stable period did you manage to get? Good for you and Good Luck! Chris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: What Do you think From: "Bryan & Regina Goss" bgoss@.................. Date: Mon, 22 Jan 2001 22:00:26 -0600 I was able to get about 17 seconds and it took about 2 hours, I almost settled for less. It seems to work great except the shop floor tilts a lot with temperature changes I must adjust every 3 to 5 days this is bothersome. Thank you for your suggestions I will use them I plan to build another one or two. ----- Original Message ----- From: To: Sent: Monday, January 22, 2001 9:36 PM Subject: Re: What Do you think > In a message dated 22/01/01, bgoss@.................. writes: > > > Well I finally got my sight updated tell me what you all think. > > The results look OK, which is what counts. > > I see that you have used both magnetic and fluid damping. With the > magnetic damping, you have used Al plate which is not nearly as effective as > Cu and you have also used a very large magnetic gap. This suggests that your > magnetic damping is a sort of 'add on' correction. The problem with fluid > damping in general is the huge changes in fluid viscosity with temperature, > particularly between summer and winter. If it works OK, don't 'fix' it. If > you want to experiment at any time, I suggest you try a bit of 1/8" Copper > plate, no fluid and reduce the magnet gap till you get ~critical damping. > This will be independent of temperature. > > You might want at some stage to fit a small underrun lamp (1/2 to 2/3 > rated voltage) inside the top of the box to give a stable temperature > gradient to the internal air. A layer or two of bubble wrap with suitable > viewing holes cut in it could provide additional insulation while still > allowing light through. A layer of polythene damp proof sheeting under the > whole apparatus could prevent any condensation problems from the flooring. If > you get any problems with lightning where you are, you might consider > mounting the amplifier on the baseplate and connecting the baseplates > together with a common earth. > > For others still in the design stage, you can get threaded Brass and > Stainless Steel rods, which are both non magnetic and so won't give problems > with magnetic interactions. Another alternative is to get plain rod and have > some thread put one end. Mounting the sensor system just inboard of the > weight can give a more compact system. Socket cap screws can make levelling > adjustments easier to perform and fine threads are available - it is a bit > easier to get an extension rod into a hole than a flat screwdriver bit into a > slot. > > What stable period did you manage to get? > > Good for you and Good Luck! > > Chris > __________________________________________________________ > > 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: missing instructions From: "George Harris" gjharris@............. Date: Tue, 23 Jan 2001 13:01:25 -0800 ----- Original Message -----=20 From: Ed Ianni=20 To: psn-l@................. Sent: Wednesday, January 17, 2001 7:03 PM Subject: missing instructions Would anyone out there know where I could get the instructions for a = "Perkin Elmer r 100 a" chart recorder? Thanks, Ed. Ed, I have a Perkin Elmer R50 recorder with a complete manual. The unit = is 13x17x5 inches. It has speed control from 10 mm/hr to 60 cm. per = minute. It uses paper 11 1/8 inch wide on a drum which is about 1.3 = inch diameter. If this is similar to your recorder, I may be able to = help. The manual has about 60 pages. =20 George Harris gjharris@.............
 
----- Original Message -----
From:=20 Ed = Ianni
Sent: Wednesday, January 17, = 2001 7:03=20 PM
Subject: missing = instructions

Would anyone out there know where I = could get the=20 instructions for a "Perkin Elmer r 100 a" chart recorder? Thanks,=20 Ed.
 
Ed,
 
I have a Perkin Elmer R50 recorder = with a=20 complete manual.  The unit is = 13x17x5=20 inches.  It has speed control from 10 mm/hr to 60 cm. per = minute. =20 It uses paper 11 1/8 inch wide on a drum which is about 1.3 inch=20 diameter.  If this is similar to your recorder, I may be able to = help.=20 The manual has about 60 pages. 
 
George Harris
gjharris@.............<= /DIV> Subject: help-me From: agustri agustri@......... Date: Thu, 25 Jan 2001 08:57:35 +0700 Help me, I am not yet clear about the difference of 1.displacementmeter, velocitymeter and accelerometer also 2.shortperiod, longperiod and broadband seismometer, Tanks for your kindness. Regards, Agus Tri Sutanto, MGA, Indonesia __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: QUAKE??? From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 25 Jan 2001 21:17:58 -0600 Local small quake near me in Mississippi something went by at about 3:10 = UTC it seemed small but close????
Local small quake near me in = Mississippi something=20 went by at about 3:10 UTC it seemed small but=20 close????
Subject: East Coast - Lake Erie Quake From: Brian Zimmerman bzimmerman@............ Date: Thu, 25 Jan 2001 22:47:08 -0500 We just had a felt quake on the South Shore of Lake Erie. I'm quessing M 3-4 anyone else get it ? This will be big news here. Brian Zimmerman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: help-me From: ChrisAtUpw@....... Date: Thu, 25 Jan 2001 22:41:45 EST In a message dated 25/01/01, agustri@......... writes: > I am not yet clear about the difference of > 1.displacementmeter, velocitymeter and accelerometer also > 2.shortperiod, longperiod and broadband seismometer, Hello Agus Tri Sutanto, Consider a weight on the end of a very long pendulum. When an earthquake happens, the ground will move a certain distance while the pendulum weight stays nearly still. Measuring this will give the displacement, usually measured in microns. If, instead of measuring the displacement, you use a coil of wire on the ground and put a magnet on the weight, you will get a signal which depends on the rate of movement of the ground - it's velocity. If you connected the weight to the ground with a 'load cell', which measures force, the weight will now have to follow the ground movement and you will get an output which is proportional to the acceleration of the ground. In a simple system like the pendulum, it will tend to have one particular frequency or period at which it oscillates naturally, like in a clock. Now we want to measure the ground movements, not the oscillation of a pendulum, so the movement is 'damped', maybe by putting a paddle on the weight and letting it dip into a container filled with oil, resting on the ground. The weight can still move, but if you give it a light push, it deflects a small distance and then moves back to the original position, but not past it. The name short, or long, period seismometer refers to the natural period of the apparatus when it is not damped. A Shakleford-Gunderson seismometer may have a period of less than a second and this would be called short. The popular Lehman seismometer may have a period of 10 to 20 seconds and this would be called long. The response of a damped seismometer changes at the natural oscillation frequency, but there is no peak output at any particular frequency. A broad band seismometer is constructed so that it gives a output which does not depend on the frequency of the earthquake signal over quite a wide range. Obviously there are both upper and lower frequency limits to the behavoir. Prof. Erhard Weilandt of the University of Stuttgart has written a very full account in his paper "Seismic Sensors and their Calibration", which is available on-line at We just had a felt quake on the South Shore of Lake Erie. I'm quessing M >3-4 anyone else get it ? > >This will be big news here. > >Brian Zimmerman 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: East Coast - Lake Erie Quake From: "D. Hill" n0ssy@......... Date: Fri, 26 Jan 2001 04:08:02 +0000 Receiving a nice seismogram here in Denver. Dewayne __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: QUAKE??? From: "Don Wheeler" wheelwx@........... Date: Thu, 25 Jan 2001 22:17:54 -0600 Where in Mississippi are you located? I'm just north of Monroe, LA. I'll check to see if I got anything. >From: "Bryan & Regina Goss" >Reply-To: psn-l@.............. >To: >Subject: QUAKE??? >Date: Thu, 25 Jan 2001 21:17:58 -0600 > >Local small quake near me in Mississippi something went by at about 3:10 >UTC it seemed small but close???? _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: QUAKE??? From: "Bryan & Regina Goss" bgoss@.................. Date: Thu, 25 Jan 2001 22:22:23 -0600 I am in the northeast corner of the state in Corinth, about 50 miles north of Tupelo. Thanks!!! ----- Original Message ----- From: Don Wheeler To: Sent: Thursday, January 25, 2001 10:17 PM Subject: Re: QUAKE??? > Where in Mississippi are you located? I'm just north of Monroe, LA. I'll > check to see if I got anything. > > > >From: "Bryan & Regina Goss" > >Reply-To: psn-l@.............. > >To: > >Subject: QUAKE??? > >Date: Thu, 25 Jan 2001 21:17:58 -0600 > > > >Local small quake near me in Mississippi something went by at about 3:10 > >UTC it seemed small but close???? > > _________________________________________________________________ > Get your FREE download of MSN Explorer at http://explorer.msn.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: Re: East Coast - Lake Erie Quake From: The Lahrs johnjan@........ Date: Thu, 25 Jan 2001 21:27:52 -0700 NEIC located the event near Ashtabula, Ohio. 01/01/26 03:03:19 41.99N 80.83W 5.0 4.2Lg A OHIO http://neic.usgs.gov/neis/bulletin/ John At 09:08 PM 1/25/2001 , you wrote: >Receiving a nice seismogram here in Denver. > >Dewayne >__________________________________________________________ > >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. * 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: Another quake From: "Larry Conklin" lconklin@............ Date: Thu, 25 Jan 2001 23:35:45 -0500 There is something else going on that is a heck of a lot bigger than the Ohio quake, but apparently much farther away. I have been getting a very strong signal for about an hour here in central NY. Larry Conklin lconklin@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Another quake From: Seisguy@....... Date: Thu, 25 Jan 2001 23:37:18 EST In a message dated 1/25/01 8:36:29 PM Pacific Standard Time, lconklin@............ writes: > There is something else going on that is a heck of a lot bigger than the > Something big just happened in India... In a message dated 1/25/01 8:36:29 PM Pacific Standard Time,
lconklin@............ writes:


There is something else going on that is a heck of a lot bigger than the
Ohio quake, but apparently much farther away.


Something big just happened in India... Subject: Re: East Coast - Lake Erie Quake From: "bobshannon.org" earth@........... Date: Thu, 25 Jan 2001 20:37:30 -0800 ----- Original Message ----- From: Brian Zimmerman To: Sent: Thursday, January 25, 2001 7:47 PM Subject: East Coast - Lake Erie Quake > > > We just had a felt quake on the South Shore of Lake Erie. I'm quessing M 3-4 anyone else get it ? > > This will be big news here.more information. If this is true and holds I would appreciate all input for my Pinpoint subscribers as well as ELFRAD who is monitoring eastern quakes very closely this last few days... I do NOT represent ELFRAD..I am only a reader, but I am owner of Pinpoint since 1992 Bob __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: East Coast - Lake Erie Quake From: Seisguy@....... Date: Thu, 25 Jan 2001 23:41:05 EST Strong quake felt most strongly in western India NEW DELHI, Jan 26 (Reuters) - Residents in western and northern India felt strong tremors for about 30 seconds on Friday. There was no word on casualties or damage. A meteorological department official in New Delhi said there had been an earthquake, but said he needed 10 minutes to confirm the epicentre and intensity. People in the western state of Gujarat, which is prone to earthquakes of up to seven on the open-ended Richter scale, said they felt the tremor very strongly. "The building shook so much that it developed cracks," said Vinay Kumar, who works for Gujarat Petroleum Corp. "It was like being on a swing. Nobody could get out for those 20 or 30 seconds." Residents in New Delhi said buildings swayed and furniture moved about from about 8:50 a.m. (0320 GMT). Many people ran out of their houses into the street. The quake was also felt in Bombay, which is around 1,400 km (875 miles) from the capital. "It was quite gentle," said a Bombay resident. "It lasted about two minutes. I felt the dressing-table shaking and the bed as well." The last major earthquake to hit India was in March 1999. Measuring 6.8 on the Richter scale, the quake and its aftershocks killed 100 people and injured 300 in the Himalayan foothills and was felt across many parts of northern India, western Nepal and southern China. 23:04 01-25-01 Strong quake felt most strongly in western India

 
NEW DELHI, Jan 26 (Reuters) - Residents in western and northern India felt
strong tremors for about 30 seconds on Friday.

There was no word on casualties or damage.

A meteorological department official in New Delhi said there had been an
earthquake, but said he needed 10 minutes to confirm the epicentre and
intensity.

People in the western state of Gujarat, which is prone to earthquakes of up
to seven on the open-ended Richter scale, said they felt the tremor very
strongly.

"The building shook so much that it developed cracks," said Vinay Kumar, who
works for Gujarat Petroleum Corp. "It was like being on a swing. Nobody could
get out for those 20 or 30 seconds."

Residents in New Delhi said buildings swayed and furniture moved about from
about 8:50 a.m. (0320 GMT). Many people ran out of their houses into the
street.

The quake was also felt in Bombay, which is around 1,400 km (875 miles) from
the capital.

"It was quite gentle," said a Bombay resident. "It lasted about two minutes.
I felt the dressing-table shaking and the bed as well."

The last major earthquake to hit India was in March 1999. Measuring 6.8 on
the Richter scale, the quake and its aftershocks killed 100 people and
injured 300 in the Himalayan foothills and was felt across many parts of
northern India, western Nepal and southern China.

23:04 01-25-01
Subject: Another bigger quake somewhere... From: "meredith lamb" mlamb1@.......... Date: Thu, 25 Jan 2001 21:42:41 -0800 Hi all, Getting bigger surface waves at ~04:35, from somewhere, and it wouldn't be the mag 4.2 quake. Unless.....its a bigger shock in that area??? Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: East Coast - Rueters From: Seisguy@....... Date: Thu, 25 Jan 2001 23:42:53 EST Minor earthquake reported in northeastern Ohio GOLDEN, Co., Jan 25 (Reuters) - A minor earthquake with a magnitude of 4.2 shook northeastern Ohio on Thursday evening, and tremors were felt as far away as Toronto, Canada, a spokesman for the U.S. Geological Survey said. The quake occurred at about 10 p.m. EST (0300 GMT) and its epicenter was recorded 10 miles (16 kms) north-northeast of Ashtabula, Ohio, said Bruce Presgrave of the agency's National Earthquake Information Center. He predicted little if any damage, given the relatively low preliminary magnitude measurement, but said the quake was felt in Erie, Pennsylvania and Toronto. 23:41 01-25-01 Minor earthquake reported in northeastern Ohio

 
GOLDEN, Co., Jan 25 (Reuters) - A minor earthquake with a magnitude of 4.2
shook northeastern Ohio on Thursday evening, and tremors were felt as far
away as Toronto, Canada, a spokesman for the U.S. Geological Survey said.

The quake occurred at about 10 p.m. EST (0300 GMT) and its epicenter was
recorded 10 miles (16 kms) north-northeast of Ashtabula, Ohio, said Bruce
Presgrave of the agency's National Earthquake Information Center.

He predicted little if any damage, given the relatively low preliminary
magnitude measurement, but said the quake was felt in Erie, Pennsylvania and
Toronto.

23:41 01-25-01
Subject: 6.5 Pakistan quake From: "Frank Cooper" fxc@....... Date: Thu, 25 Jan 2001 23:01:36 -0600 Red Puma reports a 6.5 in Pakistan at 03:16:51, 1/26. It is still = clipping the chart recorder here. Frank Cooper, Friendswood, Texas
Red Puma reports a 6.5 in Pakistan at 03:16:51, = 1/26.  It=20 is still clipping the chart recorder here.
Frank Cooper, Friendswood, Texas
 
 
Subject: Re: 6.5 Pakistan quake From: "Don Wheeler" wheelwx@........... Date: Thu, 25 Jan 2001 23:18:03 -0600 Alaska Tsunami Center reported a prelim. of 8.3. Feel this is a bit too high. My recorders just stopped clipping but still getting strong waves. TSUNAMI BULLETIN NUMBER 1 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED JAN 26 AT 0353 UTC ....THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 8.3, OCCURRED AT 1817 AST ON JAN 25, OR 1917 PST ON JAN 25, OR 0317 UTC ON JAN 26. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: SOUTHERN INDIA NEAR 23.6N, 70.2E. EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. IN AREAS OF INTENSE SHAKING, LOCALLY GENERATED TSUNAMIS CAN BE TRIGGERED BY SLUMPING. THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS WARRANT.IF AVAILABLE, REFER TO THE INTERNET SITE HTTP://WCATWC.GOV FOR MORE INFORMATION. >From: "Frank Cooper" >Reply-To: psn-l@.............. >To: >Subject: 6.5 Pakistan quake >Date: Thu, 25 Jan 2001 23:01:36 -0600 > >Red Puma reports a 6.5 in Pakistan at 03:16:51, 1/26. It is still clipping >the chart recorder here. >Frank Cooper, Friendswood, Texas > > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: East Coast - Lake Erie Quake From: Stephen & Kathy mortskm@....... Date: Thu, 25 Jan 2001 20:30:33 -0800 You may be recording the large event from India, Pakistan region. I started recording it about 03:35:44 UTC Jan 26,,,, I'm now recording the surface waves. It is about 8,000 miles from my station,, it is going to be well over a 7 mag!! Stephen PSN Station #55 near Pilot Hill Ca 38.828N 120.979W "D. Hill" wrote: > Receiving a nice seismogram here in Denver. > > Dewayne > __________________________________________________________ > > 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: BIG QUAKE ! From: "I.ES.N." info@........ Date: Fri, 26 Jan 2001 06:58:46 +0100 just terminated now the record of a very big quake Preliminary location INDIA-PAKISTAN BORDER REGION Ms 7.6 / 7.8 or more....!!!!!!! No report yet by international agencies Francesco Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MS7.9 SOUTHERN INDIA From: "Frank Cooper" fxc@....... Date: Fri, 26 Jan 2001 00:16:46 -0600 USGS has now posted a Ms7.9, SOUTHERN INDIA, 01/26/01, 03:16:41 Frank Cooper, Friendswood, Texas, USA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: 6.5 Pakistan quake - Ohio Quake From: Brian Zimmerman bzimmerman@............ Date: Fri, 26 Jan 2001 01:31:16 -0500 Things are slow in the Lake Erie snow-belt in January. A M4.2 is big news. So far I've been live on all 3 local news shows and interviewed by 2 papers. While the news crews were filming, the surface waves from Pakistan were coming through. Thanks to everyone out there on the PSN I had a suspicion that there was a large quake somewhere else and did not embarrass myself by assigning these large surface waves to the local event. There was no way you were all recording our little quake. Even less possible that the surface waves were local. The last news crew got to film what looks to be the first after-shock at approximately 05:40. Can't remember when I have had this much fun Brian Zimmerman Edinboro University of PA -----Original Message----- From: Frank Cooper [SMTP:fxc@........ Sent: Friday, January 26, 2001 12:02 AM To: psn-l@.............. Subject: 6.5 Pakistan quake << File: ATT00002.html >> Red Puma reports a 6.5 in Pakistan at 03:16:51, 1/26. It is still clipping the chart recorder here. Frank Cooper, Friendswood, Texas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: MS7.9 SOUTHERN INDIA From: Brian Zimmerman bzimmerman@............ Date: Fri, 26 Jan 2001 01:34:08 -0500 After posting my last message I received the latest on the larger quake. Sitting here in the middle of a plate we forget how dangerous these things are. Hope it was in a remote area. BZ -----Original Message----- From: Frank Cooper [SMTP:fxc@........ Sent: Friday, January 26, 2001 1:17 AM To: psn-l@.............. Subject: MS7.9 SOUTHERN INDIA USGS has now posted a Ms7.9, SOUTHERN INDIA, 01/26/01, 03:16:41 Frank Cooper, Friendswood, Texas, USA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BIG QUAKE ! From: "Dennis Epperly" seaarch@...... Date: Thu, 25 Jan 2001 21:35:53 -0900 Hello from Alaska. I live on Cook Inlet which one side has the Alaska Range which has several active volcanoes, three of which have erupted in the last 15 years. From my home I can see three active volcanoes. We had a 5.0 quake last night 8:30 P.M. 30 miles due west from my house with a depth of 47 miles. It was a short quick one couple of little vibrations the three big jolts. Our area here is in constant motion with a subduction zone running up from the Aleutian trench into Cook Inlet were it meets the pacific, west coast fracture zone. Our activity has increased down by Kodiak Island which is on the east side of the subduction zone with about five volcanoes on the west side which includes Katmi, which had the second largest volcanic eruption in our recorded history. When Katmi went off if the eruption was in New York you would of been able to hear it in Chicago. I'm thinking that a volcano is working it's way to the surface on the south end of Kodiak Island, because of the number of quakes in that area in the last year, or so with a couple of quakes in the upper 7 range. I hiked into the Katmi area and took photos of the vent< nova eruptus, which was on the valley floor several thousand feet from the summit of Katmi caldera. The vent is now plugged with a lava plug which is hot and steams. I'm sending a photo of the lava dome, side view with the valley below which is still desolate by the eruption almost 100 years ago. Thanks for your time Dennis ----- Original Message ----- From: "I.ES.N." To: "PSN" Sent: Thursday, January 25, 2001 8:58 PM Subject: BIG QUAKE ! > just terminated now the record of a very big quake > Preliminary location INDIA-PAKISTAN BORDER REGION > Ms 7.6 / 7.8 or more....!!!!!!! > No report yet by international agencies > > > Francesco Italy > > > __________________________________________________________ > > 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: earthquake updates From: "Ed Ianni" edwianni@........ Date: Fri, 26 Jan 2001 01:46:48 -0500 If anyone has Netropa internet receiver (it's free at the netropa = website)... it is reporting on these earthquakes now (and does = continuously) with a map, etc. Ed.
If anyone has Netropa internet receiver = (it's free=20 at the netropa website)... it is reporting on these earthquakes now (and = does=20 continuously) with a map, etc. Ed.
Subject: Sending attachments. Please read. From: "Larry Cochrane" cochrane@.............. Date: Fri, 26 Jan 2001 00:17:56 -0800 All, Please do not send attachments to the list. If you have a file you would like to share with the group please place it on a server somewhere and send us the link to the location of the file. Thanks, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BIG QUAKE ! From: The Lahrs johnjan@........ Date: Fri, 26 Jan 2001 04:19:46 -0700 Hi Dennis, Great photograph! There is probably no direct connection between the 4 large events that occurred near southern Kodiak Island and any of the volcanoes in the region. Three of the four occurred within the subducted Pacific plate and were due to stretching of the plate as it is pulled into the mantle. The most recent one was on the thrust boundary between the underthrusting Pacific plate and the overriding North American plate. All of these events are indicative of continued subduction, which is the process that leads to volcanism, but they are not directly related to any particular future eruption. You're certainly living in a hot spot for big earthquakes, so take every precaution. Cheers, John At 11:35 PM 1/25/2001 , you wrote: >Hello from Alaska. I live on Cook Inlet which one side has the Alaska Range >which has several active volcanoes, three of which have erupted in the last >15 years. ... * 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: Tsunami list server From: "D. Hill" n0ssy@......... Date: Fri, 26 Jan 2001 14:16:49 +0000 Can someone tell me where I can subscribe to a Tsunami list server? Dewayne __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: India Quake From: Jeff Batten jeff.batten@........ Date: Fri, 26 Jan 2001 11:46:56 -0800 Hello, Where can I find a web site that has specific info on the quake. Fault Rupture Length Accelerations Thanks Jeff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: India Quake From: The Lahrs johnjan@........ Date: Fri, 26 Jan 2001 20:46:49 -0700 Hi Jeff, The USGS has this page with information: http://neic.usgs.gov/neis/eqhaz/010126.html but I think it's too early for the specific information you are looking for. John At 12:46 PM 1/26/2001 , you wrote: >Hello, > >Where can I find a web site that has specific info on the quake. > >Fault >Rupture Length >Accelerations > > >Thanks > >Jeff John C. Lahr lahr@........ (work) john@........ (home) Central Region Geologic Hazards Team U.S. Geological Survey PO Box 25046 Denver, CO 80225 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: India Quake From: BOB BARNS roybar@........ Date: Sat, 27 Jan 2001 09:24:03 -0500 John, I looked at the "Live web camera" on the site given below. For the station NEW, 12 heliocorders are shown (labeled short period vertical). Why 12 drums for short period vertical? Why make recordings on paper? Bob Barns The Lahrs wrote: > > Hi Jeff, > > The USGS has this page with information: > http://neic.usgs.gov/neis/eqhaz/010126.html > > but I think it's too early for the specific information > you are looking for. > > John > > At 12:46 PM 1/26/2001 , you wrote: > > >Hello, > > > >Where can I find a web site that has specific info on the quake. > > > >Fault > >Rupture Length > >Accelerations > > > > > >Thanks > > > >Jeff > > John C. Lahr > lahr@........ (work) > john@........ (home) > > Central Region Geologic Hazards Team > U.S. Geological Survey > PO Box 25046 > Denver, CO 80225 > __________________________________________________________ > > 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: If you felt the quake it was scary From: Stacey Martin 9point1@....... Date: 27 Jan 2001 22:09:23 IST Hi, I wish I could have set up my PSN station, but I haven't and have th= us missed the biggest quake we've had in 50 years. I did feel it though and = that was scary enough. I'm roughly 725 kilometers SE of the epicentre. I was o= n my computer at the time (about 8:50am IST) and though I was feeling guidy. T= hen the curtains and things around began to gently swing. It wasn't a fast jerking, but more of a a relatively slow side-to-side shaking. I immediat= ely ran into a doorframe and from there watched in awe as the water in my aqu= arium began to slosh back and forth !!!!! It lasted around 20 seconds. I then r= an into the balcony and saw my windchimes still winging and in the opposite apartment building, on the 4th floor, a suspended lamp was swinging back = and forth, in an east-west direction. At the time I was too excited and calle= d up a few friends who hadn't felt a thing. Th