2011年東北地方太平洋沖地震による津波解析結果から再検討する巨大津波の発生様式

Abstract

Review of the previous tsunami analyses for the 2011 Tohoku-oki earthquake indicates that the large slip of more than 40m was estimated on the plate interface near the Japan Trench. The plate interface near the Japan Trench was previously ruptured by the tsunami earthquakes such as 1896 or 1611 Sanriku tsunami earthquakes. Along the subduction zone off Sumatra, the 2004 great Sumatra earthquake ruptured the plate interface near the trench with a large slip amount of 29m. There were also tsunami earthquakes such as the 1907 Sumatra earthquake or 2010 Mentawai earthquake which ruptured the plate interface close to the trench. These evidences suggest that occurrence of the large earthquakes which rupture the plate interface near trench such as tsunami earthquakes is more common than that we thought previously. Variability of the great earthquakes along the plate interface makes us difficult to evaluate future great interplate earthquakes along subduction zones.