The equipment SONAR is used to determine the

SONAR (Sound Navigation and Ranging) is an equipment that utilizes sound propagation to navigate, communicate, or detect objects under the water surface. It is primarily used to determine the depth of the seabed and generate bathymetric maps [t2]. The system functions as an echo sounder, mapping the sea bottom by transmitting sound beams and recording the travel time for the echo to return from the floor [t6]. While specialized Doppler sonar can measure the relative speed of a moving vessel [t1][t3], its fundamental and most common application in marine science is measuring water depth and identifying underwater topography [t4][t8]. In contrast, earthquake intensity is measured by seismometers, and aircraft altitude is typically determined using radar altimeters or barometric pressure sensors [t5][t7][t9].

Sources

1. [1] https://www.science.gov/topicpages/s/sonar+imaging+system.html
2. [2] https://ntrs.nasa.gov/api/citations/19710005316/downloads/19710005316.pdf
3. [3] https://www.sciencedirect.com/topics/engineering/air-surveillance