Scientists at the NOAA Vents Program at Pacific Marine Environmental Laboratory and Oregon State University heard the March 11, 2011 Honshu, Japan earthquake using a hydrophone located near the Aleutian Islands of Alaska. The normal low frequency of the earthquake sound in the water would not be audible to a human swimmer. On this video, the earthquake sound has been sped up so that it plays back at a higher frequency which we can hear.
For information on the underwater microphones, see http://www.pmel.noaa.gov/vents
For tsunami information, see See http://nctr.pmel.noaa.gov/honshu20110311
