Base on the study of Jianghai Xia et al. (Xia et al., 2007), we put forward another way to use the generalized S-transform of Rayleigh waves to detect the shallow subsurface voids.

The arrival times of the diffracted Rayleigh waves from the near and far-offset boundaries of the void, which are extracted by the generalized S-transform, are used to calculate the boundary locations of the void.

The theoretical models and the real world example showed that it is feasible and effective to use the generalized S transform to detect the near-surface cavities.