【摘要】 收集了国际上发布的通过日本区域密集的地表观测数据获得的高精度同震形变位移,同时收集了靠近震中的5个海底基准点观测到的同震变形。基于以上结果采用分断层滑动模型,基于分层弹性半空间位错理论,采用二阶拉普拉斯平滑算子方法约束断层面上的滑动量,利用最速下降法求解模型的最优解,以期精化该地震断层的滑动分布,进而研究其地震活动机制。研究结果表明,日本地震断层的平均滑动为6.95m,最大滑动量为58.70m,位于东经143.17°,北纬38.25°,地震所释放的能量为4.48×1022 N.m(等效震级为Mw9.07),地震断裂主要集中于东经142°～143.8°,北纬37.2°～39.5°,海平面以下10～30km之间区域。更多还原

【Abstract】 The Mar 11th 2011 Tohoku earthquake(Mw=9.0) is located in northeastern of Japan.The surface observation data were rapidly obtained using the dense continuously GPS stations covered the island after the earthquake broking.In this paper,the reliable co-seismic deformation field is derived from GPS measurements using the highly precise data processing method and sea-floor points set near the epicenter.The co-seismic fault slip distributions are further inverted to explore the seismic mechanism using the steepest descent method to get the optimal solution.The second-order Laplace smoothing operator method had been used to constrain the fault slip amplitude based on the layered elastic half-space homogeneous model.The inversion results show that the energy released by the earthquake is about 4.48 × 1022 N·m equivalent to moment magnitude Mw 9.07.The average fault slip is about 6.05m while the maximum slip is about 58.7 m at 143.17 degrees east longitude and 38.25 degrees north latitude according the GPS and sea-floor points observed co-seismic deformation.The seismic fault characteristic is mostly thrust slip slide at the epicenter while some strike slip slide at the edge of faults.更多还原