基于多模式的多重滤波方法提取瑞雷面波频散曲线

The Extract Dispersion Curves of Rayleigh Surface Wave Based on Multiple Filtering Method

为了验证多重滤波方法对两道地震信号提取频散曲线的有效性,通过设计层状与倾斜介质模型,采用交错网格高阶有限差分法进行正演模拟,利用F-K变换分离出时间—空间域不同模态瑞雷面波记录,再利用多重滤波法对频散曲线进行提取,将求取的相速度和群速度与相移法、互相关法提取结果并与理论值进行对比分析。结果表明:利用多重滤波法提取瑞雷面波频散曲线是可行的,且能够提取到高阶模式频散曲线。多重滤波法在低频段更具有稳定性,横向分辨率更高。最后通过实例证实了多重滤波方法的实际效果。

In order to verify the validity of the multiple filtering method for extracting dispersion curves of two seismic signals,the finite difference method of high-order staggered grid is used to carry out forward modeling by designing layered and inclined media models in this paper.F-K conversion is used to separate time-space domain of different modes of Rayleigh wave recorded,and then the dispersion curve is extracted by using the multiple filter.Finally,the extracted phase velocity and group velocity are compared with the re-sults and the theoretical values extracted by phase shift method and cross-correlation method.The results show that it is feasible to extract the Rayleigh wave dispersion curve with multiple filters and to extract the dispersion curve of high order mode.Multi-filter method in the low frequency band has more stability and higher horizontal resolution.Lastly,an example is given to demonstrate the practical effect of the multiple filtering method.