Seismic diffracted waves from topography using 3-D discrete wavenumber‐boundary integral equation simulation
Seismic diffracted waves from topography using 3-D discrete wavenumber‐boundary integral equation simulation
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DOI：
10.1190/1.1444564
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发表时间：
1999-04
期刊：
影响因子：
3.3
通讯作者：
S. Durand;S. Gaffet;J. Virieux
中科院分区：
文献类型：
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作者：
S. Durand;S. Gaffet;J. Virieux
自由表面地形的纵波(P)和横波(S)衍射在地震风险估计的场地反应预测中起着重要作用。为了准确估计这些衍射，需要三维介质中的波传播建模。我们推广了不规则地形三维几何的离散波数-间接边界积分方程方法。利用地形的空间周期性和表面的离散化，格林函数被表示为水平波数上解析密度函数的有限和。我们证明了解析积分在垂直波数kz上的计算是可能的，因为在1/k2中存在一个新的因子。当施力点和受力点处于同一垂直位置时，我们制定了一种数值策略来选择指数因子的符号，这是解析公式无法给出的。在地形上的自由应力边界条件导致了一个大的线性…
Compressional (P) and shear (S) wave diffraction by free‐surface topography plays a prominent part in the prediction of site responses for seismic risk estimation. Wave propagation modeling in 3-D media is required for an accurate estimation of these diffractions. We have extended the discrete wavenumber‐indirect boundary integral equation method for a 3-D geometry in the case of irregular topography. The Green’s functions are expressed as finite sums of analytical density functions over the horizontal wavenumbers using the spatial periodicity of the topography and a discretization of the surface. We show that the evaluation over vertical wavenumber kz of the analytical integral is possible because a new factor in 1/k2 exists. When the force point and the receiver point are at the same vertical position, we develop a numerical strategy to choose the sign of the exponential factor, which is not given by the analytical formulation. The free‐stress boundary conditions at the topography lead to a large linear...