Seismic surveys use sound waves to image the subsurface and identify potential hazards, such as faults, fractures, and sinkholes.
Magnetic surveys use magnetic fields to identify potential hazards, such as buried metallic objects and magnetic rock formations.
Electrical resistivity surveys use electrical currents to measure the electrical conductivity of the subsurface. This information can be used to identify potential hazards, such as groundwater contamination and voids in the subsurface.
GPR uses high-frequency radar waves to image the subsurface and identify potential hazards, such as buried utilities and archaeological features.