Surface wave interferometry by crosscorrelation and deconvolution

Frequency analysis of surface waves is an efficient tool to retrieve the vertical shear-wave velocity profile. Surface waves result from the interaction of elastic body waves with a free surface. They are commonly generated by impulsive sources but are also present in ambient noise. Here we compare the results of interferometric estimation of surface-wave dispersion from controlled noise sources by using both cross-correlation and deconvolution methods. The crucial step in both methods lies in the dispersion image computation that conditions the reliability of the dispersion curve, and therefore the inversion results. We have found that the dispersion characteristics of surface waves are better defined when the deconvolution method is used. This better definition is probably due to the relative independence of the deconvolved output from the source function.