USGS: Mapping of the Puerto Rico Trench Sound Waves 03 USGS http://soundwaves.usgs.gov/2003/10/fieldwork.html Sound Waves 03 USGS Sound Waves 03 USGS http://soundwaves.usgs.gov/2003/10/fieldwork.html http://soundwaves.usgs.gov/2003/10/fieldwork.html map and learn more