针对三维波动弹性动力方程推导谱元法算法，考虑三维真实地形及介质的衰减特性，基于并行计算环境，采用谱元法和etop1'数据，对首都圈一个4.7级地震的地形效应进行模拟。模拟结果表明，在考虑地形效应情况下，模拟台站记录与实际观测记录更为一致，地形对地震波速度竖直分量的影响要大于两个水平分量，高PGA区域多分布于山顶与山脊；与平坦地形相比，PGA相对地形放大系数为-20.4%-174.6%，不同地点的垂直向速度及加速度分量波幅遵循峰顶、山脊得到放大的模式。与已有二维模型计算结果相比，三维真实地形对地震动的影响更为复杂。
The effects of topography on seismic ground motion of an MS 4.7 earthquake in Capital region were simulated based upon elastodynamic equation for 3D wave propagation, the spectral-element method, parallel computation environment, incorporated realistic 3D topography and attenuation of media. The simulated results show that the simulated time series is consistent with the recorded data much better; topographic effects due to great rough terrain on vertical components of seismic wave are bigger than those on two horizontal components. Large PGA values are almost located near mountain tops and ridges. Compared with the model without topography, the relative topographic amplification factors of PGA in the zone near the epicenter are -20.4%-174.6%, while the Z velocity component at different sites are in accordance with the pattern of amplification on mountain tops and ridges, and there is a decrease in valleys and brooks. It can be concluded that the effects of 3D realistic topography on seismic ground motion are more complex than those of the existing 2D generalized mode1.
2017,38(1): 7-14 收稿日期：2014-10-31
DOI：10.3969/j.issn.1003-3246.2017.01.002
基金项目：中国地震局地球物理研究所中央级公益性科研院所基本科研业务专项（项目编号：DQJB12B17）
作者简介：廖力(1983-),男,四川人,助理研究员,主要从事地球动力学数值模拟相关研究工作
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