Simulations for seismic wave propagation in the sedimentary basin over half-infinite rock space were performed in this analysis. The results indicated that the basin shape in heterogeneous structures affected wave dynamic characteristics in propagating. The refraction wave from the rock brought the multireflection wave and the secondary surface wave in the basin. The waves oscillating up-down within the basin shook the buildings time after time resulting in heavy damage. The geometrical

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... by basin corners and the physical interference between waves significantly amplified the ground motions. The location of peak ground motion due to the interference was attributable to the apparent velocity difference between the secondary surface wave and the body wave. The late-arrival waves also resulted in the peak ground motion. The frequencies of the late-arrival waves of multireflection might cause dispersion. The late-arrival conversion waves with various frequencies widened the frequency band of seismic input waves shaking buildings and could seriously damage buildings with corresponding intrinsic frequencies.