2013年Ms 7.0级中国芦山地震断层曲面模型的构建及其滑动分布的大地测量反演

Construction and Geodesy Slip Inversion Analysis of 2013 Ms 7.0 Lushan in China Earthquake's Curved Fault Model

根据中国芦山地震的余震序列分布和地质构造情况,联合GPS同震位移和水准测量数据,采用格网搜索法和方差分量估计(variance covariance component,VCE)方法建立了芦山地震的断层曲面模型。以建立的断层曲面模型为基础进行滑动分布反演,反演结果表明此次地震以明显的逆冲滑动为主,存在左旋趋势,断层的滑动主要发生在4.56~18.25km深度范围内,最大滑动量为0.70m,在深度12.64km附近,释放的能量为8.77×10^(18) N/m(相当于Mw 6.57级)。对曲面模型进行棋盘检验,结果表明其能够较好地分辨出断层深度浅于13km的凹凸体,其面积最小为8km×8km。

Based on the distribution of aftershock sequences and the geology of Lushan,using the GPS and level measurement coseismal displacement data near the Lushan Earthquake,we constructed a curved fault model of the 2013 Ms 7.0 Lushan earthquake using the grid search and variance component estimation method.We executed a fault slip distribution inversion based on this curved fault model.The result shows that the fault is mainly a thrust fault with a sinistral trend.The earthquake occurred at 4.56~18.25 km in depth,the maximum slip was 0.70 mat the 12.64 km depth,and the corresponding seismic moment release was 8.77×10^（18） N/m,equivalent to a Mw 6.57 earthquake.Based on a check board test of the curved fault model,we can distinguish an asperity shallower than13 km in the fault depth,with a minimum area of 8 km×8 km.