Know how to use "fewer" and "less"? Find out.
trade name for an acoustic detector that responds to ground vibrations generated by seismic waves. Geophones-also called jugs, pickups, and tortugas-are placed on the ground surface in various patterns, or arrays, to record the vibrations generated by explosives in seismic reflection and refraction work. They also are used as military detection devices. See also seismic survey.