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Output of a computer model of underwater acoustic propagation in a simplified ocean environment. A seafloor map produced by multibeam sonar. Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries.
While the audio profile of Bloop does resemble that of a living creature, [4] the source was a mystery both because it was different from known sounds and because it was several times louder than the loudest recorded animal, the blue whale. [5] The NOAA Vents Program has attributed Bloop to a large icequake. Numerous icequakes share similar ...
While terrestrial animals often have a uniform method of producing and detecting sounds, aquatic animals have a range of mechanisms to produce and detect both vocal and non-vocal sounds. [7] In terms of sound production, fish can produce sounds such as boat-whistles, grunts and croaks using their swim bladder or pectoral fin.
Underwater acoustic communication is a technique of sending and receiving messages in water. [1] There are several ways of employing such communication but the most common is by using hydrophones . Underwater communication is difficult due to factors such as multi-path propagation , time variations of the channel, small available bandwidth and ...
The speed of sound will vary slightly depending on temperature, pressure and salinity; and for precise applications of echosounding, such as hydrography, the speed of sound must also be measured, typically by deploying a sound velocity probe in the water. Echo sounding is a special purpose application of sonar used to locate the bottom.
The SOFAR channel acts as a waveguide for sound, and low frequency sound waves within the channel may travel thousands of miles before dissipating. [5] This phenomenon is an important factor in submarine warfare. The deep sound channel was discovered and described independently by Dr. Maurice Ewing, and Leonid Brekhovskikh in the 1940s. [6]
A hydrophone can also detect airborne sounds but is insensitive of them because it is designed to match the acoustic impedance of water, a denser fluid than air. Sound travels 4.3 times faster in water than in air, and a sound wave in water exerts a pressure 60 times more than what is exerted by a wave of the same amplitude in air.
Acoustic wayfinding, the practice of using auditory cues and sound markers to navigate indoor and outdoor spaces; Animal echolocation, animals emitting sound and listening to the echo in order to locate objects or navigate; Echo sounding, listening to the echo of sound pulses to measure the distance to the bottom of the sea, a special case of sonar