Viscoelastic wave simulation in basins by a variable-grid finite-difference method
Viscoelastic wave simulation in basins by a variable-grid finite-difference method
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DOI：
10.1785/0120000236
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发表时间：
2001-12
影响因子：
3
通讯作者：
Yibo Wang;J. Xu;G. Schuster
中科院分区：
文献类型：
--
作者：
Yibo Wang;J. Xu;G. Schuster
介绍了一种变网格有限差分方法，用于三维盆地中粘弹性波传播的数值模拟。盆地模型包括用细网格模拟的近地表松散层和用粗网格模拟的深部。FD方法在一定深度处改变所有三维中的网格间距，以提供计算成本的显著降低。它是对其他变网格有限差分方法的改进，它可以适应2×和3×网格间距的变化，并通过波数域的三维插值方案克服了可能的不稳定问题。以一个盐湖盆地模型为例，采用变网格法模拟了该盆地的三维粘弹性响应。仿真结果表明，三维盆地特征和浅层对地震动的幅值和持续时间有显著影响。没有浅低速层的盆地模型低估了地面运动持续时间和累积动能的50%或更多。在这种情况下，与标准FD方法相比，可变网格方法需要的CPU时间（和物理内存）少5倍。
A variable-grid finite-difference (FD) scheme is introduced for efficiently modeling viscoelastic wave propagation in 3D basins. The basin model includes a near-surface unconsolidated layer that is modeled with a fine grid and a deep part that is modeled by a coarse grid. The FD method changes the grid spacing in all three dimensions at a certain depth to provide a significant reduction in computational cost. It is an improvement on other variable-grid FD methods in that it can accommodate both 2× and 3× grid-spacing changes and a possible instability problem is overcome by a 3D interpolation scheme in the wavenumber domain. As an example, the variable-grid method is used to simulate the 3D viscoelastic response of a Salt Lake basin model. Simulation results show that the 3D basin features and the shallow layer significantly affect the amplitude and duration time of the ground motion. A basin model without a shallow low-velocity layer underestimates the ground-motion duration and cumulative kinetic energy by 50% or more. In this case, the variable-grid method requires 5 times less CPU time (and physical memory) compared to a standard FD method.