PSN-L Email List Message

Subject: Re: dynamite blast recordings
From: "tdick" dickthomas01@.............
Date: Thu, 16 Oct 2003 20:00:03 -0500

----- Original Message ----- 
From: "Jim ODonnell" 
Sent: Thursday, October 16, 2003 7:02 PM
Subject: Re: dynamite blast recordings

> Hi Dick -- first name Tom, last Dick - old german ancestry

Can you describe your system,

Larry Cochrane's boards and software -- magnetic induction coils
One vertical -- actually a 10 lb (approx) horsemagnet suspended on a spring,
dampened vertically in oil and for torque with magnets -- 

I can "see" anything the local Universities show on their seismometers
locally and most earthquakes around the world that are 6 or more
magnitude, -- I have difficulty picking up mag 3 at the shallow depths in
California from here in southern Indiana -- Lehmans are not as sensitive

two Lehman's one north-south and the other east-west tuned to about 8
seconds --  orientation checked ahead of time by compass

setup below ground level in basement

sensitivity -- well not calibrated yet but I can "see" the cat sitting on
the floor in the room with the units scratching her ear, I can "see" walnuts
falling off the tree onto the screened-in porch roof attached to the house
about 25 ft away from the units and the difference between my
daughter-in-law and my son walking into the house to feed the cat when we
were gone

 how many components, sensor specs-
> do you know the polarity of the sensors- Run a tap or tilt test?    no

 How far away are the blasts?  least distance about 30 miles and the
fartherest at least 120 miles -- there is an underground mine as well

I have one confirmed dynamite blast located by St. Louis using the local
seismometer (SIU) and IU at Bloomington, IN that was 34 miles away -- my
software correlated with this one

> Also can you post or send me some data to look at?

If you have the time --- give me an email address; do you want the original
data or Winquake? I don't have a web site.


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