Please see noise.
Measurements (in decibels) of sound levels in water are not equivalent to those in air. In air, a level of 120 decibels is painful for humans. In water, it takes 195 decibels to make divers equally uncomfortable.
level in dB
|220||Air guns used in geophysical surveys|
|209||Heard Island experiment (1991)||270 dB|
|up to 220||dolphins|
|underwater volcanic eruptions & earthquakes|
|150||polar ice pack|
|boat with outboard motor|
|130||breaking waves, 30-knot wind|
According to John R. Potter, Marine Physical Laboratory, Scripps Institute of
Oceanography, as reported in:
Malcolm B. Browne.
Human noises in ocean held to threaten marine mammals.
New York Times, page B5, October 19, 1993.
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Last revised: 18 May 2002.