Hydrophones
The US (and probably other) Navy operates hydrophone networks to track submarines. There's other listening posts. When the USS Scorpion collapsed underwater, research hydrophones in Newfoundland and the Canaries caught the sound and triangulation helped narrow the search.
A lot of tape had to be analysed to determine which noise was the collapse event.
There would be an acoustic event if an intact hull (or big enough piece) hit at speed. But would the sound propagate in shallow water to wherever a hydrophone would pick it up -- provided that there's any hydrophones that would pick up acoustic events in the area.
Navies are very secretive about where their hydrophone networks are placed.