The use of seismic sensors to find intruders dates back to the Vietnam War.
They were placed along the Ho Chi Min trail, a network of paths from North
Vietnam to South Vietnam that also crossed into Laos and Cambodia.  The
sensors were modified US Navy sonobuoys, and about 20,000 were dropped along
the trail.  There were two versions, one stuck into the ground like a lawn
dart, and the other was dropped by parachute, and could remain above ground.
The signals were picked up by nearby airplanes and relayed to ground
stations.

Bob Hancock
Three Points, AZ  

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Connie and Jim Lehman
Sent: Saturday, September 23, 2006 07:28
To: psn-l@..............
Subject: Re: Border Patrol Use Of Seismic Sensors

Geoff--just a few thoughts here on  sensitivity with proximity detectors of
motion type.  I don't have a lot of experience with them, but the 3
dimensional accelerometers--that's the closest to a chip I have seen)--
highly amplified I am sure would do the trick 30 paces or more away.
Probably with regular instrumental amplifiers a buried mike at two feet
would copy surface motion within 50 ft.  In our work, we were looking for
running water in underground limestone channels.  Of course one has to put
up with false alarms of animals, wind,rain--(rain sounds unique 2 ft
under!!!) Etc.
   Best wishes,   Jim Lehman
----- Original Message -----
From: "Geoffrey" 
To: "PSN" 
Sent: Saturday, September 23, 2006 5:33 AM
Subject: Border Patrol Use Of Seismic Sensors


> I understand the US Border Patrol has used
> seismic sensors for a long time now to watch
> certain areas of the border for intruders/interlopers
> and I was wondering what is the sensors they
> are using (make and model or type or manufacturer)?  Does anyone know ??
>
> I can imagine the military doing this too
> around nuclear sites and such
> critical areas where sensitive
> information is being collected/stored.
>
> I happen to know that geiger counters can now
> use semiconductor sensors instead of those old
> delicate tubes with relatively short lives
> due to the organic quenching gases.
> So I can imagine there exists today
> sensors we have never seen before that are
> far superior to what us amateurs have been
> exposed.
>
>
> Why cant a seismic sensor be built into
> a microchip somehow ??
>
> Have the experts in the field of science
> (scientists) ever experimented here ?
>
> Are there any military secrets related to Geology ?
> (that might help us)
>
> Anyone here know anything about the future of
> vibration sensors sensitive enough and low noise enough
> down to or below the seismic
> noise level ?
>
> Regards;
> Geoff
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