基于多模式分离的S变换与小波变换提取面波频散曲线对比分析

A comparative study of surface wave dispersion curves extracted from S transform and wavelet transform based on multi-mode separation

为了对比分析小波变换和S变换在计算瑞雷波频散曲线时的精度,通过设计两层介质和六层介质模型,采用交错网格高阶有限差分方法对两个模型进行正演模拟,利用F-K法分离出时间—空间域不同模态的瑞雷波记录,再采用小波变换和S变换计算出不同模态的瑞雷波频散曲线,分别与理论值进行对比分析,最后利用两种方法对实际资料进行处理。结果表明:利用小波变换计算得到的频散曲线在低频段误差相对较大,S变换计算得到的频散曲线精度总体高于小波变换。

To compare and analyze the dispersion accuracy of Rayleigh wave calculated by wavelet transform and S transform, the au-thors applied staggered grid high-order finite difference method to two-layer model and six-layer model designed by the authors, then the Rayleigh wave records of different modes in time-space domain were isolated by using F-K method, and Rayleigh wave dispersion curves of different modes were calculated by using wavelet transform and S transform in comparison with the theoretical values. Finally, the two methods were used to deal with real data. The results shows that the error in the low frequency of the dispersion curve calculated by wavelet transform is relatively large and the accuracy of the dispersion curve calculated by S transform is higher than that calculated by wavelet transform on the whole.