Doing more with seismographs

[Jeff Z]

Greeting fellow earthquake enthusiasts,

With the app on my phone from CSEM, I get quite quick notifications of large earthquakes. I received a notification of the Kamchatka quake yesterday quite quickly after it occurred and was able to watch it live on my monitor for at least a couple of hours. It was quite amazing to be able to see the waves from the quake for that long. The planet was ringing quite a bit after that one.

For all the many years that I have had my seismometer running, all I have ever done was just see the record they left on the monitor, do the P and S wave and distance calculations using Larry's software and save them somewhere. I also play a little game with my family I call, "Find the Earthquake".  I take a picture of the monitor which shows the quake and they try and find the quake. I also send a picture with the start and end points of my record of it highlighted as some are a bit more of a challenge than others. Also a copy of the calculation of the quake I get with WinQuake so they can see the distance and such.

I have been thinking that there should be more I could do with my seismometer? Some more science? 

One thing I would like to be able to see (?) is the P & S waves from great earthquakes like this that come the long way around. I see the P, S and ground waves that come directly to me from wherever the quake occurs. And with large quakes like this, I can see them for a long time, a good two hours in this case. Shouldn't my seismometer be able to see the P and S waves that come the long way around? Is there a way to know when they arrive?

I have been trying to find out how to do that but have not had any luck researching that. I found a paper on "Seismic Waves and Earthquake location" by J.R Kayal. It has been very interesting, but I have not read anything about finding the P&S waves the long way around. I also have a copy of "Seismicity of the Earth and associated Phenomena " by Gutenberg and Richter, which I have not read yet, but plan to soon.

I was hoping that people here in the group could lead me in the direction to learn how to discover the "long way around P&S waves". Also, any other science that I could be doing with my system but don't know what that could be.

I have a homemade Lehman seismometer and am using Larry's WinSDR and WinQuake.

I still find seismology and earthquakes utterly fascinating and would like to pursue this a little bit further.

Thank you,

Jeff Z

Calgary, Canada

[James Skinner]

- Jeff -

Just a wild idea.  You may be able to use the computer "filters" to filter out the long period waves and be

able to see the P & S coming around the long path.

I also got the initial notification soon enough after the event to capture the whole thing.  It "Rang" the

earth here for more than 2 and a half hours and still was giving my enough ground motion here in

Tucson that it was comparable ground motion that I would compare it with what I'd have from a 4.x mag

event from the lower San Andreas.

Jim Skinner, K6BPT

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[Jeff Z]

Thank you James, hadn't thought of that. I will have to give that a try. 

Jeff

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[James Skinner]

- Jeff -

Good luck with that, the only instrument that I have on line here at the moment is a Guralp 40T

3 component 30 second to 50 Hz seismometer. At the moment my vertical channel is not

functional so when I pull it off of the instrument pier to repair it, I'll fire up the remaining seismos

and get them back on line. During the summer, it gets over 130 °F in the seismo hut so I don't

get in there very often.

Been doing this since the mid-1960's when working "McNamara's Wall" (Vietnam) most of our

Unattended Ground Detectors (counter personnel) used Geophones for detection of troop and

material movements throughout S. Vietnam.

Jim Skinner

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[Stephen Hammond]

PS Thanks for offering CSEM Last Quake- just installed it- looks interesting, S

On Wednesday, July 30, 2025 at 12:31:31 PM UTC-7 Stephen Hammond wrote:

Hi I need to look at CSEM — I noticed the event on my PSNsanjose site and if I’m not alert, would have missed the event. WInsdr captures a continues record and I replay the event in Winquake which does generate P&S makers.

It would be nice to have an automated process.

Just a comment where is my soap box? it’s great to see others are still actively recording events. I was beginning to believe I was the last of the few PSN stations still active. Happy to see all the responses! I want to also thank Larry for keeping his Redwood City PSN site going and maintaining the info and event database. Following the recent GOV reductions, the USGS appeases to be on autopilot after Dr’s Lucy Jones, kate Hutton and, Susan Hough departed. There has been nothing but silence following a M8.8 earthquake from the people in charge. NOT a word has been spoken by a human; all I have seen are automated push message’s not even an AI image of an earthquake icon/meme.

— At this point I have eight seismographs online and the data is updated every 15min to the web.  See the events tab on www.PSNsanjose.com.

Regards from Aptos,CA — Steve

Sent from my iPhone

On Jul 30, 2025, at 11:07 AM, James Skinner <k6b...@gmail.com> wrote:



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[Stephen Hammond]

Hi Jim-- FYI, I still have 4 Geotech 87000Cs horizontal long-period in storage, complete and last time I checked in working order... FREEeeeee!  S--

[Stephen Hammond]

Hi Jeff, I just looked at your distance from the 8.8 event, 5,608km from the epicenter. My Aptos station is 6,083km from the event—my event file 250729.232400.atv.psn and atw.psn are on Larry's Redwood City system; https://www.seismicnet.com/cgi-bin/event. Using Winquake to view the data, they should match up reasonably well. If you have a printout you are using for the "Find the Quake" game, our stations are almost the same distance from the epicenter. You can also use the crop feature under the data tab in Winquake to extract specific data for examination. Please give it a look, as you can also reset the P&S markers and place them where you desire. Steve Hammond

[James Skinner]

Hello Steve... very long time no confab.  I still have a Sprengnether S-5100-V and S-5500-H

as well as S-13 (verticals), L-4C (horizontal) on a 9600 Lb instrument pier and a "Swamp Pack"

3 component 4.5 Hz Geophone (buried in the yard on a separate 275 Lb instrument pier).

Had a couple of computers go titsup on me that were running 2/3rd's of my instruments.

I still need to reload Win SDR back on the replacement computers.

 

Have  a medium period homebrew Vertical built on the base of an old freight scale and an old

S-13, 1 Hz vertical "jug" sitting on the floor in the garage.

Jim Skinner, K6BPT

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[Jeff Z]

Hi James,

I gave it a try and it didn't seem to work for the "long way around" waves. It did let me see the P &S waves for the M6.9 aftershock that I couldn't see due to the waves from the main quake.

Thanks for the idea though. I will remember it for aftershocks that I can't see in the future.

Jeff Z

On Wed, Jul 30, 2025 at 12:07 PM James Skinner <k6b...@gmail.com> wrote:

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[Stephen Hammond]

I'm happy to report and correct my previous post; I also need to apologize to the USGS Seismology Group here in the Bay Area. At 3 p.m. today on KCBS radio, I heard a seismologist from the Northern California USGS Earthquake Science Center at Moffett Field, CA give a live press conference. Two main points. 1) An 8.8 earthquake in the Bay Area is very unlikely. 2) The 8.8 in Russia was the 6th largest recorded earthquake in history. 

My further research found the Center holds Zoom news/press conferences (we need to check into when and how), and here is a URL for the Center. https://www.usgs.gov/centers/earthquake-science-center/connect

With a great deal of information.

Regards, Steve Hammond PSN San Jose.

[Dave Buckowski]

Hi Steven,

I'm in Central California and I can definitely use two of your Geotech 87000Cs horizontal long-period detectors!

Please let me know how to proceed.

And of course I will pay shipping!

Thank you,

Dave Buckowski

Clovis, California

On Wed, Jul 30, 2025 at 12:47 PM Stephen Hammond <shamm...@gmail.com> wrote:

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[Jeff Z]

Hi Steve, thanks for the comments. I see your events on Larry's site all the time. I am always impressed by how many events you post there. 

I will give your events a look and compare them to mine. I hadn't thought of that. It will be interesting. I have a busy weekend coming up, but I will give it a look next week.

And that CSEM app is great. It gives really quick notices of quakes and I have been able to watch quite a few big quakes live. They recently redid the layout and I am still figuring it out, but the notices still come quickly for me to watch them if I am home or awake.

Jeff Z

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[Stephen Hammond]

Hi Dave, they are free. Just to be clear, they should not be sold; they were given to me for the PSN by a retired member. I live in Aptos, 6miles south of Santa Cruz. All you need to do is pick them up. They were intended to go to Cabrillo College, but the teacher moved out of the area. Send me an email offline at shamm...@gmail.com, and we can make the arrangements. 

Steve