How do sound channels in the ocean work?
There is a depth in the ocean where a sound can travel for thousands of miles without fading.
The answer
The SOFAR (Sound Fixing and Ranging) channel is a horizontal layer in the ocean, typically at around 600 to 1,200 meters depth, where the speed of sound reaches a minimum due to the combined effects of decreasing temperature and increasing pressure. Sound waves entering this channel are continually refracted back toward the axis of minimum speed, becoming trapped and traveling extraordinary distances with minimal energy loss. During World War II, the U.S. military developed the SOFAR system to locate downed pilots by listening for the sound of small explosive charges they dropped into the water. Today, scientists use the SOFAR channel to monitor underwater earthquakes, volcanic eruptions, and whale calls across entire ocean basins.
Source: Acoustical Society of America
- SOFAR channel
- ocean acoustics
- sound propagation
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