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Which sonar frequencies are used to measure ocean depth?

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To measure ocean depth, sonar systems utilize specific acoustic pulse frequencies depending on the intended scientific or navigational objective.

For the primary purpose of measuring ocean depth, acoustic pulses of 12 kilohertz (kHz) are typically employed.1

Other frequency ranges are utilized for different underwater mapping tasks:
* Sediment Mapping: Lower frequencies, ranging from 3.5 kHz to less than 100 hertz (Hz), are used to determine the thickness of sediments within ocean basins.1
* Seafloor Texture: Very high frequencies of 100 kHz or more are used in side-scanning sonar to measure the texture of the seafloor.1
* General Depth Finding: In some sonic depth-finding applications, audible frequencies of less than 15 kHz are commonly used.2

These systems operate by converting electrical energy into acoustic pressure waves via a transducer, then measuring the time elapsed for the pulse to reflect off the seafloor and return to the source.21