Doug,

Since I am doing it for my own use on my own land or land I have 
a long time relationship with the owners I can ignore almost all 
of the problems you outline. I am not sure you can make anything 
useful that will meet today's pc safety standards. I don't think 
the hammer and planks would be free of liability. Where I am I 
think I can still get dynamite unless it has changed since 9/11. 
But the shot gun shell down the tube sounds the best.

I am only interested in a pretty homogenous mix of sand and 
gravel  over a red bed looking for courser gravel. I can wait 
until it highly saturated if I have to. It happens ever 2 or 3 
years. I know the output of  every well for about 5 square miles 
and I have access to 3 wells in a mile and half that put out 
enough water to build  a drip irrigation system if I can find 3 
more on one quarter section that is as good or better that the 
one I have.

We have dug test well several times over the last 50 years and 
only found one good well.

If I find any promising areas the farmer and I are going to try 
jetting down a 4 inch well. He has lots of farms in the same 
area that have better water than my place but the cost of 
commercially drilled and developed well are too high for 
landlords to invest in 4 or 5 to feed an irrigation system.

Right now I am working on the sensors and recording them. A 
laptop would be nice for the reason you give. I can do it with 
an A/D  board as well. But I will try the sound card first.

Fortunately I have some friends that have hands on experience 
with reading seismic data. We all have questions about being 
able to see the difference in the gravel sizes and the porosity 
of the sands. The 75 gpm well I have is 150 feet from one that 
you can run dry with a garden hose in an hour.

Gordon

Doug Crice wrote:
 > For as long as I have been in seismic, people have been 
trying to build a
 > good energy source for engineering seismic studies.  Let me 
define such a
 > device for you experimenters out there.
 >
 > 1) A person ought to be able to carry it around
 > 2) It needs reasonably high frequency output (ping instead of 
thunk)
 > 3) Build it for $1000 or even $2000 in lots of 10 units, 
using new
 > commercially available and machined parts.
 > 4) It should be safe, even when used by students
 > 5) There should be no significant regulatory issues (a 
problem with
 > dynamite, the perfect source)
 > 6) Operating supplies available in third world countries.
 > 7) And last but not least, it needs to work better than a 
sledgehammer used
 > with a seismograph that can stack multiple impacts.
 >
 > The in-hole shotgun comes close, but it is possible to shoot 
yourself in the
 > foot, blow your hand off, and in one case, blow your brains 
out.  The
 > associated liability prevents any real company from producing 
the device.
 > Even if you made it impossible to accidentally hurt yourself, 
under our tort
 > system, you would still be liable for intentional injuries.
 >
 > Geostuff will be happy to sell the device using our worldwide 
network of
 > contacts, assuming it works and is reliable. Mechanical 
things tend to self
 > destruct.
 >
 > Doug Crice          http://www.geostuff.com
 > Wireless Seismic            http://www.wirelessSeismic.com
 > 12996 Somerset Drive                phone 1-530-274-4445
 > Grass Valley,  CA  95945  USA    fax 1-530-274-4446
 >
 >
 >
 > I know a gun fired in the ground is not a good source and that's
 > why I included a drop hammer lifted by a bank and dropped back
 > on the rod that is attached to a steel plate that sets on the
 > ground. I may have to use a propane to lift the slide over the
 > piston instead of a blank shot gun shell,
 >
 >
 >
 >
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