[jedc]

Active sonar (where a device sends a pulse of energy & listens to replies) can impact marine life.

Passive sonar (where you just listen to acoustic energy in the water) is used by submarines and surface ships to find submarines. With both on-board and towed sonar.

Submarines don't have any sonar designed to map the sea floor, though there are tools to identify the depth below the keel at any given time. Creating proper maps of the sea floor are done by much more specialized equipment/systems/processes. https://en.wikipedia.org/wiki/National_Geospatial-Intelligen...