What are these???

Yesterday while out, we passed this convoy of vehicles that were being escorted front and rear by cop cars...there were five of them in single file line, and they had the logo of "Dawson Geophysical" on each side of their doors...have never seen anything close resembling these vehicles before...what are they?

thumpers
 theyare used to thump the ground so they can read the sound waves looking for gas

idk but i want one

gas or oil... sounds badass but it doesnt scare any livestock around either... cool setup

Look at those tires!  If I put those on my truck I could float across the lake.

those are owned by dawson geophysical co. I work security for them. I am usually one of the guys in the squad car. The tires on those things are 66x44x25. they even have more aggresive tires they can put on them depending on the area they are working in. the trucks are called vibe trucks. they have a center section that is pushed down to the ground and it vibrates the ground via a system that uses compressed nitrogen.
When the trucks go thru neighborhoods they place monitors up by houses to ensure they are not shaking the foundation to much.

seismic surveying, pretty cool on how it all works.

Witnessed the aquatic version first hand a few years ago on Eagle Mountain Lake.  Pretty cool how they look for gas pockets...not seen the Thumpers before though

Been doing a little research on this since I posted the question up...I have to say I'm a bit skeptical about the government's reports that there is no evidence of any negative lasting effects as a result of the "thumping" on the Earths surface.
 
http://www.pittsburghlive...moreland/s_702633.html
http://www.riverreporter....-18/news-thumpers.html
http://www.wisegeek.com/w.t-is-a-thumper-truck.htm