基于二维有限单元法的芦山M7.0地震近场强地面运动模拟

基于2013年芦山M7.0地震近场区域深反射剖面和P波、S波层析成像资料，使用接触单元模拟断层非线性破裂过程，利用二维有限元法模拟芦山地震强地面运动。在信度检验的基础上研究震源应力降和粘聚力参数对于水平向基岩地震动参数的影响。研究发现，芦山地震上盘场址处水平地震动峰值加速度明显大于下盘场址处结果，且衰减速度更慢，呈现上下盘效应特征；应力降和粘聚力对地表水平向基岩地震动均具较为明显的正向影响作用，其中应力降对0.05～1.00 s短周期成分作用明显，粘聚力则对1.00～6.00 s中长周期成分具有显著影响。

Simulation of Near Field Strong Ground Motion of Lushan M7.0 Earthquake Based on Two-Dimensional Finite Element Method

According to the geophysical data obtained in the near field of the Lushan M7.0 earthquake in 2013, including the deep reflection profile and the result of P wave and S wave tomography, we establish the two-dimensional finite element model. The contact element is used to simulate the discontinuous behavior of the faults, and the numerical simulation results of the strong ground motion are further given. The results show that the ground motion parameters on hanging walls are larger than those on footwalls at the similar rupture distances, which we call the hanging-wall/foot-wall effects of near-fault ground motions. At the same time, the stress drop and cohesive force parameters have obvious positive effects on ground surface horizontal bedrock ground motion. The stress drop plays a significant role in the short period components in 0.05 s-1.00 s, and cohesion has a significant effect on the medium and long period components of 1.00 s-6.00 s.