基于GPS和水准数据的2013年芦山7.0级地震震源滑动模型

GPS AND LEVELING CONSTRAINED CO-SEISMIC SOURCE AND SLIP DISTRIBUTION OF THE LUSHAN M_S7.0 EARTHQUAKE ON 20 APRIL 2013

利用GPS连续站和精密水准观测资料得到的同震形变结果作为2013年芦山7.0级地震地表3维形变场的约束,在兼顾不同断层模型方案的基础上对地震震源参数等进行了反演计算,结果表明:以盲逆断层作为反演的断层模型优于以上边界到地表的断层作为反演的断层模型的结果,矩形盲逆与铲状盲逆断层模型间的反演结果没有明显的差异,芦山地震矩的最佳反演结果为M_W6.7,位错在断层面上的分布集中在30km×30km的范围内,以逆冲为主兼有北翼右旋,南翼左旋的特征,左旋分量大于右旋分量,是一种"楔型"形变模式。

Co-seismic deformation results calculated by the observations of GPS continuous sites and precise leveling are used as three-dimensional constraints for the deformation field of Lushan Ms7.0 earthquake on 20 April 2013.The inversion of seismic source parameters are calculated based on the consideration of different value-taking schemes and fault models. Seven data type selection schemes, three fault models and two data coverage selection schemes are designed in order to discuss the effect of data selection and fault model selection on the inversion results. The results show that the fault model using blind reverse fault for the inversion is superior to the model using the fault that ruptures from its upper boundary to the earth＇surface, which may indicate that the Lushan earthquake fault is most likely a blind reverse fault; there are no obvious differences in the inversion results between the blind listric reverse fault models and the rectangle blind reverse fault models. The best inversion result of Lushan earthquake seismic moment is Mw6.7.And it also shows that the distribution of dislocations on the fault plane is concentrated in the range of 30km×30km, the northern flank of the seismogenic fault of Lushun earthquake is of dextral faulting and the southern flank of the fault is of sinistral faulting, the sinistral component is larger that dextral component, showing a wedge deformation mode.