Side-scan sonar
Side-scan sonar is a technique of archaeological survey in nautical archaeology. It uses a sonar device that emits pulses down toward the seafloor across a wide angle. It can detect large objects lying on the seafloor that are completely invisible in the murky seawater. The sound frequencies used in side-scan sonar usually range from 100 to 500 kHz; high frequencies yield better resolution but less range.
Side-scan sonar was developed in the 1960s. Important contributors included Harold Edgerton.
