Refraction surveys determine the depth and P wave velocities of =
materials.
As a general rule, when you hit the water table, the velocity is 5000
ft/sec. Though other materials can have the same velocity, it's =
typically
water table and that becomes one of the layers.

However, you need to work a little harder if you're siting a water well. =
You
would be more interested in the bedrock contours or fracture zones, and =
it
might be good to mix in some electrical methods as well.

Doug Crice
Geostuff             http://www.georadar.com/geostuff.htm
12996 Somerset Drive                phone 1-530-274-4445
Grass Valley,  CA  95945  USA    fax 1-530-274-4446
=20

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of BOB BARNS
Sent: Wednesday, July 28, 2004 5:10 PM
To: psn-l@..............
Subject: Re: ebay auction

Doug,
   Thanks for taking the time to characterize these things.  Could it be =

used to find subsurface water?
Bob Barns
   PS:The "photo of borehole geophones" on your website did not come up=20
for me.

Doug Crice wrote:
> This is an exploration seismograph (not an earthquake seismograph)
designed
> for refraction surveys using a sledgehammer as an energy source. This =
type
> of instrument is commonly used to map subsurface geology (e.g. depth =
to
> bedrock) down to a maximum of 30 meters. It looks like everything is =
there
> except the aluminum striker plate and of course a sledgehammer.
>=20
> Read about refraction surveys here
> ftp://geom.geometrics.com/pub/seismic/Literature/s-tr2.pdf
>=20
> Doug Crice
> Geostuff             http://www.georadar.com/geostuff.htm
> 12996 Somerset Drive                phone 1-530-274-4445
> Grass Valley,  CA  95945  USA    fax 1-530-274-4446
> =20
>=20
> -----Original Message-----
> From: psn-l-request@.............. =
[mailto:psn-l-request@...............
On
> Behalf Of BOB BARNS
> Sent: Wednesday, July 28, 2004 10:54 AM
> To: psn mail
> Subject: ebay auction
>=20
> Hi gang,
>     	SEISMOGRAPH scientific instrument by GEOMETRICS nr	 Item
> number:=20
> 2259633751=09
>    ends Aug. 2
> Bob Barns
>=20
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