A geothermal survey around Munich is using vibrotrucks to send controlled vibrations into the ground while a large network of geophones records the reflections. The project covers roughly 1,000 square kilometers, with more than 120,000 recording locations and about 86,000 planned vibration points.

Hackaday's Elliot Williams encountered the trucks in his neighborhood and followed them in the field. The vehicles press an exciter plate against the ground and sweep through low frequencies so researchers can reconstruct underground layers in 3D.