Coseismic Tsunami simulation assuming the displacement of high-angle branching active faults identified on the continental slope around the Japan trench

Abstract

The aim of this study is to demonstrate the tsunami potential caused by high-angle branching faults with relatively low net slip compared to that of the 2011 off the Pacific coast of Tohoku (Tohoku-oki) earthquake of Mw9.0, located in the upper part of the mega-thrust along the Japan Trench where the Tohoku-oki earthquake ruptured, as deduced from the distribution of active faults illustrated by a bathymetric geomorphological study and seismic profile records (Nakata et al. Active faults along Japan Trench and source faults of large earthquakes. http://www.jaee.gr.jp/event/seminar2012/eqsympo/pdf/papers/34.pdf. 19 Dec 2012). The results show that the expected tsunami from high-angle branching faults becomes about one and a half times as high as the case of low-angle thrust faults. This demonstrates the importance of the distribution of high-angle branching faults on the continental slope and their subsurface structure in tsunami hazard assessment.