BOUNDARY ELEMENT-PERTURBATION METHOD USING NEUMANN SERIES EXPANSION FOR SEISMIC RESPONSE ANALYSIS OF THE GROUND WITH IRREGULAR SURFACE

It has been pointed out that the ground with an irregular surface causes complicated seismic responses. However, the process of generating this complex response is not yet clarified. In this study, boundary element-perturbation method has been developed to investigate scattering of seismic waves due to an irregular surface. This method is based on the boundary element method in frequency domain and perturbation technique employing the Neumann series. By using this method, the ground response can be separated into those induced by incident waves and scattered waves. Numerical results showed that the amplitudes of the scattered waves are affected by both distance and direction of the irregular surface to the observation points.