Simulation of the seismic response of sedimentary basins with constant-gradient velocity along arbitrary direction using boundary element method: SH case

We presented a boundary element method using the approximate analytical Greenos function given by SȢnchez-Sesma et al. Coordinate transform is introduced to extend the method to deal with the model with constant-gradient velocity along oblique direction. The method is validated by comparing the numerical results with other independent methods. This method provides a useful tool for analyzing local site effects. We computed seismic response for two series of models. The results in both frequency and time domains are analyzed and show complex amplification patterns. The fundamental mode of resonance is dependent not only on the velocity at the free surface but also on the velocity distribution of the whole basin. For the higher modes of vibration the heterogeneous basin also has its own characteristic.