According to the U.S. Geological Survey, the earthquake occurred at a depth of 15.2 miles (24.4 kilometers) beneath the seafloor. This map shows the location of the March 11 earthquake, as well as the foreshocks (dotted lines) and aftershocks (solid lines). The size of each circle represents the magnitude of the associated quake or shock. The map also includes land elevation data from NASA’s Shuttle Radar Topography Mission and ocean bathymetry data from the British Oceanographic Data Center.