マグニチュード9クラスのプレート境界地震による強震動予測のための断層モデルの設定方法: 南海トラフ巨大地震への適用と東海地方における強震動の試算例

摘要

The feature of great subduction plate-boundary earthquakes such as the 2011 off the Pacific coast of Tohoku, Japan, earthquake (M_w 9.0) and the 2004 Sumatra earthquake (M_w 9.1) is that the short-period motions were generated on the deeper part of the fault and the long-period motions on the shallower part. Hence, we compiled the fault parameters of past subduction earthquakes and showed their scaling laws. Then, we proposed a procedure for making a consistent fault model both for the deeper part and the shallower part, applied our new procedure to the large subduction earthquake (M_w 9.1) along the Nankai trough off the Pacific coast of the West Japan, and showed four examples of the fault models including several asperities. Based on the four examples, we simulated ground motions in and around Nagoya City by the empirical Green's function method, and compared the seismic intensities of the simulated motions with those in the past three Nankai trough earthquakes.%本論文では、マグニチュード9クラスのプレート境界地震の強震動を予測するいう観点で、断層モデルの設定方法を考えた。具体的には、はじめに、2011年東北地方太平洋沖地震の断層パラメータが従来の強震動予測で用いられている断層パラメータの相似則の延長線上にあることを確認したうえで、強震動と津波の予測のための統一断層モデルとしてのァスペリティモデル（地震調査研究推進本部，2005など)を提示した。