Approximate Direct Estimate of S-wave Velocity Model from Surface Wave Dispersion Curves

Surface wave dispersion curves are inverted to obtain 1D local VS model. The inversion is based on a layered model and the result is non-unique. A linear relationship can be found between weighted average S-wave velocity at different depths and surface-wave phase velocity at different wavelengths. This relationship, if known for a category of models, can be used to directly estimate an approximated velocity profile from the dispersion curve without the need for inverting. We show on a synthetic case that the error between estimated and true velocity is of the same order of that obtained by inversion.