交错网格有限差分法模拟微动信号

Simulation of Microtremor Using Staggered-Grid Finite Difference Method

为了较好地模拟给定模型在随机源激发下产生的稳定波场信息,为微动信号的检验和数据特征分析等提供理论依据,采用交错网格有限差分方法模拟微动信号,并根据瑞雷波和勒夫波的产生机理,通过测区内震源的分布情况估测微动信号中面波的组成成分。首先建立交错网格有限差分法模拟微动信号的数值模型,然后给出估测微动信号中面波组成成分的算式,最后采用典型方法数值模拟微动信号,应用空间自相关方法提取模拟信号中面波的频散曲线进行分析对比。结果表明,交错网格有限差分方法模拟得到的微动信号更符合实测结果。

In order to simulate wave field generated by random sources and provide theoretic reference for research and application of microtremor, microtremor is simulated using staggered-grid finite difference method. The composition of surface waves in the simulated microtremor is estimated based on the distribution of sources in the measured area according to the generation mechanism of Rayleigh wave and Love wave. First, we establish a numerical model for simulation of microtremor using staggered-grid finite difference method and then provide formulas to estimate the composition of surface waves. Finally, the record of microtremor is synthesized using typical methods and dispersion curves of surface waves in the simulated microtremor are extracted by spatial autocorrelation method for comparison. The results show that staggered-grid finite difference method can simulate microtremor better.