利用Yabuki & Matsu′ura反演方法计算2011年日本东北地区太平洋海域M_w9.0级地震同震滑动分布

Estimation of co-seismic slip distribution of the 2011 Tohoku-Oki M_w9.0 earthquake using Yabuki&Matsu′ura′s inverse method

Yabuki&Matsu′ura反演方法是利用ABIC最佳模型参数选取方法和平滑的滑动分布作为约束条件,由形变观测数据计算发震断层滑动分布.本文基于日本列岛同震GPS观测数据和发震断层曲面构造模型,利用Yabuki&Matsu′ura反演方法计算2011年日本东北地区太平洋海域Mw9.0级地震的发震断层同震滑动分布.反演结果表明,断层面上的最大滑动量为35m,较大滑动分布在浅于30km的震源中心上部,最大破裂集中在20km深度的地方.其地震矩约为3.63×1022 N.m,对应的矩震级为Mw9.0.模拟结果显示Yabuki&Matsu′ura反演方法更适用于倾角低于40°的断层模型反演.最后,本文基于上述方法获得的发震断层滑动模型,利用地球体位错理论正演计算该地震在中国及其邻区产生的远场形变,正演计算结果基本可以解释由中国GPS陆态网络观测到的同震形变.

Yabuki＆Matsu＇ ura＇s inverse method is to find optimum model parameters from geodetic data, combining prior information of both the smoothness of fault slip and maximum likelihood method with Akaike＇s Bayesian Information Criterion （ABIC）. We apply Yabuki ＆ Matsu＇urds inverse method to estimate the co-seismic slip distribution of the 2011 Tohoku-Oki Mw9.0 earthquake on a curve fault model from GPS observation data. The estimated maximum slip is 35 m. The strong slips are delineated in an area with depth less than 30 km, shallower than the seismic focus. The biggest ruptures moment is about 3. 63×10=N · m. concentrate in an area with depth about 20 km. The total The corresponding moment magnitude is Mw9. 0. Our simulation results confirm that the Yabuki Matsu＇urds inversion method is suitable for faults with dip angle less than 40°. Finally, we compute the far-field deformations in Northeast China of the 2011 Tohoku-Oki Mw9. 0 earthquake using spherical dislocation theory of Sun et al.. Our theoretical predictions agree well with the observed co-seismic displacement from China GPS Observation Network.