Abstract

We have built a three-dimensional layered alluvial basin calculation pattern based on the actual basin alluvial stratification. A FM-IBEM program for the arbitrary layered alluvial basin is developed, proved its applicability to the model in this paper via verification of accuracy and efficiency. Focusing on the geological complexity of real 3D basins and the broadband characteristics of incident frequency of seismic waves, we addressed the effects of incident P and SV waves in the case of different frequencies on surface displacement amplification of arbitrary layered alluvial basins. The results show that the large curvature of the alluvial boundary layer has the strongest magnifying influence on the surface displacement amplitude of the layered alluvial basin. The magnification effect of medium and high frequency SV waves on surface displacement of layered alluvial basins is less than that of P waves. But, for medium and high frequency P and SV waves incident layered alluvial basins, the surface displacement amplitude shows attenuation effect integrally.

摘要

我们在实际流域冲积分层的基础上，构建了三维分层冲积盆地计算模式。开发了任意层状冲积盆地的FM-IBEM程序，通过准确性和效率验证，证明了其对本文模型的适用性。针对真实3D盆地​​的地质复杂性和地震波入射频率的宽带特性，研究了不同频率情况下入射P波和SV波对任意层状冲积盆地地表位移放大的影响。结果表明，冲积边界层的大曲率对层状冲积盆地的地表位移幅值具有最强的放大作用。中高频SV波对层状冲积盆地地表位移的放大作用小于P波。但对于中高频P波和SV波入射层状冲积盆地，地表位移幅值整体呈现衰减效应。