Underwater Acoustics refers to the study of the production and propagation of sound underwater and the interaction of the mechanical waves that constitute sound with the water and its boundaries. It explores the theories behind sound waves in water, underwater sound density and impedance, absorption, sound reflection and scattering, and various aspects of the propagation of sound. Also taken into consideration are ambient noise, reverberation, and bottom loss.
The principles of underwater acoustics are used in sonar (Sound Navigation and Ranging), underwater communication, seismic exploration, weather and climate observation, as well as oceanography. Underwater acoustic telemetry is used in data harvesting for environmental monitoring. It is used to obtain a picture of the sea or ocean bed. It likewise aids in seismic exploration through the use of low frequency sound. Moreover, oceanography benefits from underwater acoustics by employing acoustic tomography to measure large scale ocean features through side-scan sonar and sub-bottom profiling.