Study of spatially varying ground motion under complicated ground

This paper addresses the influence of soft local site on the propagation of seismic waves. A previously developed coupled Boundary Elements-Finite Elements (BE-FE) algorithm is employed for the analysis in time domain. The Ricker wavelet with its well defined range of dominant frequencies are considered for wave incidence. The considered local site in a valley shape has a uniform soft, or a soft layer over medium subsoil bounded by a half space of hard soil. The investigation shows that the local site can significantly amplify and alter the characteristics of the propagating waves. The propagation of the seismic wave is overestimated in the complicated geological structure, The arrival time of seismic wave is different due to incident wave angel. Smaller incident angel, stronger non-uniform ground motions. Consequently, the structural response will be strongly affected.