A discussion on underwater acoustics and acoustic energy used to detect objects in the oceans or sea beds.
The following paper discusses acoustics signals that detect the presence and location of commercially useful fish, map the ocean floor to establish the safest paths for supertankers, explore the earth's geological formations and discover oil deposits in the ocean floor.
At a bottom of the permanent thermocline or below it, water temperature is uniform. Here, the pressure of the water column due to the depth takes over. The sound speeds then increase on account of increase in pressure. (Pacific) The deep sound channel axis is between 600 and 1,200 m below the sea surface at low and middle latitudes. This is deepest in the subtropics and come to the essay writing hindi language surface in high latitudes, where sound propagates in the surface layer. (Pacific) Sound waves can be trapped" in the deep sound channel and propagate in long distances. This is because these waves go through little attenuation beyond that, and this is due to geometric scattering or spread as well as minor volume scattering in water."