Geophysical tests are non-destructive methods that use physical properties of the subsurface, such as seismic waves, electrical resistance, or magnetic fields, to create an image of what lies beneath the ground. These tests are used in civil engineering and other fields to determine subsurface conditions, map geological layers and bedrock, locate underground utilities, and identify buried structures or voids without invasive drilling. Common methods include seismic surveys, electrical resistivity, and ground-penetrating radar (GPR).