thumping
n.— «Then a soldier would conduct the equivalent of what the oil industry calls “thumping.” Within the area rigged with sensors, a soldier would shoot a rifle at a small metal plate on the ground, causing reverberations anywhere from 20 to 200 feet into the ground.» —“Project lets Army dig deep into underground data” by Anne Broache CNET Aug. 22, 2005. (source: Double-Tongued Dictionary)
Further reading
Twice a day the River Thames recedes, revealing a muddy shoreline. Hobbyists known as mudlarks stroll the surface searching for objects that have found their way into the river over the centuries, everything from ancient Roman jewelry to modern...
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...