An ocean-bottom seismograph is prepared to be lowered into the ocean by the crew of the Coast Guard Cutter Oak, May 15, 2015, in the Atlantic Ocean north of Puerto Rico. The OBS, deployed by members of the U.S. Geological Survey and the Woods Hole Oceanographic Institution, is meant to record data for approximately one year to supplement data from land-based seismographs operated by the Global Seismograph Network, the Puerto Rico Seismic Network, and others. (U.S. Coast Guard photo)