Inversion of multi-mode surface waves extracted from the shallow seismic reflection data

Shallow seismic reflection and surface wave are two seismic exploration methods which are developing independently. In their respective data collection and processing, the concerned signal in one method is usually thought as the disturbed one in the other method. In this paper, the " disturbed” surface wave occurred in the data collected by shallow seismic reflection survey was reused. The dispersion curves of multi-mode surface waves were extracted in the frequency-wave number domain based on these data by applying the multi-channel surface wave technology. The S-wave velocity profiles were then inversed by taking the fundamental and/or first-order modes into account. This method fully exploited the existing data. Therefore, the special data collection for surface waves is not needed, and additional constraint is offered to the interpretation of shallow seismic reflection data. The results indicate that the reliable multi-mode dispersion curves of surface waves can be extracted from the shallow seismic reflection data, and stable S-wave velocity profile can be obtained. Meanwhile, it is concluded that the existence of low-velocity layer is the necessary rather than the sufficient condition to make the observed dispersion curve exhibit the mode-jumping among the mode branches.