矿床地球化学国家重点实验室知识库

Identification of different modes of Rayleigh waves is essential in surface-wave surveys. Multi-mode Rayleigh waves can provide higher accuracy of the near-surface structure than the fundamental mode alone. However, some modes or frequencies of Rayleigh waves may be absent in the vertical-component seismic data. To complement the dispersion information, a method based on complex-vector seismic data is proposed. We construct the complex vector by setting the radial component and vertical component as the real part and imaginary part, respectively. Then, high-resolution linear Radon transform is used to obtain the multi-mode Rayleighwave dispersion image of the complex-vector seismic data. Based on different dispersion characteristics of the radial and vertical components, the dispersion images of the complex–vector seismic data show better performance against interferences and mode misidentification. Synthetic and field examples demonstrate advantages of the complex-vector method over the traditional vertical-component method in spectral bands and dispersion curve mode identification. Therefore, a more robust and accurate near-surface S-wave velocity structure can be expected compared to the traditional vertical-component Rayleigh-wave method.