PSN-L Email List Message

Subject: Re: unusual Jan 12 quake near Bermuda?
From: The Lahrs johnjan@........
Date: Mon, 14 Jan 2002 20:56:05 -0700


I'm very impressed by you system!  You've got a good recording
of the Bermuda event.  Have you done an FFT in WinQuake to
see what the predominate frequence of your signal is?

I really like your idea of making an inexpensive system, as
cost is a major limitation for most teachers.  Are you going
to make a long period version as well?  Maybe you should check
out Meredith's levitated-graphite design as an alternative to
a large Lehman-style swinging-gate sensor.

What is involved and how difficult is it to program the PIC14000
computer?  Are you planning on providing do-it-yourself instructions
for your electronics?


At 12:16 PM 1/14/2002 , you wrote:
>While testing a 4.5 Hz geophone system near
>Washington, DC on January 12,  I seem
>to have picked up a good signal from a
>quake near Bermuda (about 800 miles away)
>Here is the WinQuake data file and plot
>Note that my time base was fast by about 290 seconds.
>Here is a WinQuake map that incorporates
>my data and PSN data from sites in NJ and
>A couple of questions:
>1. Is it unusual for a signal from a quake 800 miles
>away to have so much high frequency energy?
>2. Am I setting up the S and P markers correctly?
>My quake location seems a lot further off than
>the PSN data sets from NY and AL.  I am a
>WinQuake novice.
>I have put up a new web page on my simplified
>electronics board for a short period system:
>...Dave Saum
>Public Seismic Network Mailing List (PSN-L)
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John C. Lahr
1925 Foothills Road
Golden, CO 80402
Phone: (303) 215-9913

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