How do borehole seismic tomography works, what are the limitations.?

Answer 1

It is basically like setting up your own 3D seismic network. Seismometers are set up in a 3D grid, with boreholes spaced at regular intervals on the surface and subsurface. A source causes a propagating wave that is read by your seismic network (in 3D). Then you look for anomalies to find what you want (oil, water, ore, etc.).

The biggest limitation is price. To get the coverage/accuracy you need, lots of $$$ are needed.

Answer 2

I THINK THE TECHNOLOGY HAS CHANGED AND now they use large machines they call thumpers and it is a lot like sonar and looking at the reflectivity of the different materials.