Under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states shall establish the outer limits of continental shelf beyond 200 nautical miles when coastal states fulfill a number of geomorphological and geological criteria. Coastal states must submit information including scientific data defining the outer limits of the continental shelf to the UN Commission on the Limits of the Continental Shelf (CLCS). To prepare the necessary information by the time limit for Japan, exploration of crustal structure which is coincident with wide-angle and multi-channel seismic reflection survey has been conducted under the coordination of an interministerial council.