Development of strong motions estimation method with high precision for disaster reduction during catastrophic earthquakes

本研究提出了一种用于大地震减灾的高精度强地震动评估方法。利用经验格林函数法（EGFM）估计了2011年东北地震的短周期震源模型。用小事件运动估计了目标区域的基岩运动。根据微震的H/V谱，确定了损伤部位的速度结构。根据基岩运动和速度结构的传递函数计算的地表运动与记录的运动很好地吻合。利用EGFM计算的基岩输入运动，采用三维有限元法模拟了2009年骏河湾地震期间的地表运动。利用特征震源模型和EGFM估计的未来南开海槽地震基岩运动与日本政府的预测一致。这些结果表明，本研究开发的方法对强地面运动的评价是有用的。

This study developed a method to evaluate strong ground motions with high precision for disaster reduction during great-earthquakes. A short-period source model of the 2011 Tohoku Earthquake was estimated using the empirical Green's function method (EGFM). Bedrock motions in a target area were estimated with small event motions. Velocity structures at damage sites were identified from H/V spectra of microtremors observed there. Surface motions calculated from the bedrock motions and transfer functions due to velocity structures were well consistent with recorded motions. Ground motions on surface during the 2009 Suruga Bay Earthquake were simulated using 3D FEM from input motions on bedrock calculated by the EGFM. Bedrock motions estimated for future Nankai Trough earthquakes using the characterized source model and the EGFM were consistent with those by Japanese Government. These results show that the method developed in this study is useful for evaluating strong ground motions.