Land sonar

[Guest]

You can employee hi-res seismic but that requires an energy source , either vibe, Accelerated weight drop or shot hole.

Then there is your GPR (ground penatrating radar)

That would be your best bet.

http://www.geophysical.com/

It would be cool if the UofH had one in the geophysics dept. It would be a good project for a student.