Interference between seismic body wave and secondary surface wave resulting in the peak collapse ratios of buildings

Abstract

The ground motion in the heavily damaged zone in the 1995 Kobe earthquake, Japan was simulated in a digital seismic model by using the pseudospectral method with the staggered grid RFFT differentiation (SGRFFTD). The simulated results suggest that the heterogeneous velocity structure results in a complicated distribution of the maximum amplitudes of acceleration waveforms with peaks at the surface. Spatial distribution of the maximum amplitudes of acceleration waveforms coincides well with that of the collapse ratios of buildings in Kobe. The peaks of the collapse ratios away from the earthquake fault coincide well with the peak amplitudes of simulated seismic acceleration waves also. The interference between the secondary surface wave and the body wave results in the peak amplitude of ground motion and peak collapse ratios of buildings. Results of this analysis imply that the investigation of the structure to the bedrock is necessary for hazard evaluation and urban mitigation disaster. Seismic wave simulations are valid for aseismatic study.