2013年Ms7.0芦山地震的动力学破裂过程及其影响因素

2013年4月20日在四川芦山发生了Ms7.0地震,震源运动学反演结果给出了此次地震的破裂过程和同震滑动分布.为了更好地理解造成芦山地震破裂过程的力学原因,本文综合野外地质调查、余震定位、深地震反射剖面等结果,构建芦山地震铲型断层模型,以震源运动学反演结果为约束,将震源参数与震源附近的构造应力场结合,建立断层面上滑动量...

Simulation of rupture process and its influence factors of the 2013 MS7.0 Lushan earthquake

The M_S7.0 earthquake occurred on April 20, 2013 in Lushan, Sichuan province. The kinematic inversion on the source of this earthquake revealed the rupture process and co-seismic slip distribution of the earthquake. Based on the results of field geological survey, aftershock location and deep seismic reflection section, a listric fault model for the Lushan earthquake is constructed. In order to better understand the mechanical causes of the rupture process of the Lushan earthquake, we combine the source parameters with the tectonic stress field near the source and establish the temporal and spatial distribution relationship between the slip and traction on the fault plane. We simulate the rupture process of the Lushan earthquake by using the trial-and-error method with the given dynamic parameters based on the source kinematic inversion results and then discuss the influence of different dynamic parameters on the rupture process and co-seismic slip distribution of the Lushan earthquake. The results show that the initial stress is the key to decide whether the fault ruptures or not. The critical slip weakening displacement D_c has a great influence on the slip rate. The radius of nucleation zone and the initial stress of nucleation zone mainly affect the rate of nucleation. The local inhomogeneous fracture strength has a major effect on the fracture behavior and final slip distribution. In a word, the boundary integral equation method can effectively calculate the dynamic rupture process of the listric fault model of the Lushan earthquake and reproduce the main characteristics of the earthquake. The mechanical causes of fracture characteristics revealed by kinematic inversion results can be well explained by exploring the influence of dynamic parameters on the rupture process, which is important to understand the physical nature of seismic source process and to predict the main characteristics of the possible future earthquakes.