Indirect boundary element method solution to the seismic ground motion of near-fault sedimentary valley

In this paper, the indirect boundary element method (IBEM) is developed to solve the ground motion effect of the near-fault complex site. By establishing a two-dimensional kinematic finite fault model, the amplification effect of seismic response of sedimentary valley under the continuous dislocation of reverse faults is quantitatively analyzed. Meanwhile, the influence of the parameters such as the buried depth of the fault top, the fault dip-angle, the fault distance of sedimentary valley, the fault-plane shape, and the rupture velocity of fault on the seismic response are studied. The results show that the sedimentary valley has a pronounced amplification effect on the seismic response induced by near-fault, and the peak value of the acceleration response spectrum of the analyzed model can be amplified by 99.3%. In the sedimentary valley, the duration of earthquake motion is significantly prolonged, and the long-period velocity pulse appears, and the first velocity pulse can be amplified by 68.7%. The near-fault ground motion damages have typical concentration-effect and hanging wall effect. This study provides a new and effective method, which is of great significance for seismic zoning of complex sites near-fault. It will be of guiding significance for regional planning and seismic fortification of near-fault sites.