On 11th March 2011, Japan's largest island, Honshu, was struck by a magnitude 9 earthquake. It was triggered by a convulsive release of tension that had built up through the Pacific Plate colliding with a spur of the North American Plate. The earthquake region shall be investigated by a joint German-Japanese expedition of the RV Sonne in March and April 2012 using an ROV, AUV, multibeam, parasound, gravity corer and multicorer. The aim is to determine the changes caused by the earthquake, recover buried instruments and retrieve sediment cores.
The results will contribute to a better understanding of the course of events and the mechanisms of the earthquake and tsunami.
The epicentre of the earthquake was located 70km off the coast, and parts of the island, the shelf, and the continental slope were shifted up to 50m toward the east while the sea floor was lifted by up to 5m. As a result of these movements, including possibly large submarine slumps, a tsunami up to 40m high was created that devastated broad segments of the coast and claimed around 15,000 human lives.