在近二十年来,多道面波分析法(MASW)由于其便捷、高效等特性在浅层地震勘探领域得到了广泛的应用.本文基于多道面波勘探的采集方式,提出了一种新的面波多道分析方法——矢量波数变换法(VWTM).该方法通过对震源的近似,基于水平层状模型得到台站与震源间近似格林函数,然后进行矢量波数变换得到含有高阶模态Rayleigh波(频率-相速度)频散能量图.本研究首先利用合成地震数据到频散能量图与理论频散曲线进行叠加分析该方法的有效性和正确性;然后与相移法进行对比分析,我们发现在频散能量图中VWTM法对基阶、高阶模态成像均具有更高的分辨率和成像质量;最后我们将其应用于实际多道瞬态面波探测中,通过与相移法进行对比分析,发现VWTM法是一种方便、实用、有效的Rayleigh波频散提取方法.VWTM法提取多模态的Rayleigh波频散特征具有巨大潜力,可为基阶、高阶面波频散联合反演提供丰富的高阶模态频散信息.%In the last two decades,the Multi-channel Analysis of Surface Waves(MASW)have increasingly been used in shallow seismic exploration because of its convenience and high-efficiency.In this paper,a new multi-channel surface wave analysis based on the Vector Wavenumber Transformation Method(VWTM)is proposed.By approximating the source,we derive the empirical Green′s function between the station and the source on a horizontally layered model,and then perform vector wavenumber transformation to obtain a frequency-phase velocity dispersion energy image for Rayleigh waves.We first evaluate the performance of VWTM by using synthetic data,and compare it with theoretical dispersion curves.Comparing with typical MASW methods such as the phase shift method,we find that VWTM has higher resolution and better imaging quality for fundamental and higher modes in the dispersion energy image.Next,we apply the VWTM to the multi-channel transient surface wave exploration.Comparative analysis with the phase shift method shows that VWTM is convenient,practical and effective to reveal features of multi-mode Rayleigh wave dispersion,and provides useful information for the joint inversion of Rayleigh wave dispersion of fundamental-and higher-modes.
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