Multiscale and layer-stripping wave-equation dispersion inversion of Rayleigh waves

Abstract

Rayleigh-wave inversion could converge to a local minimum of its objective function for a complex subsurface model. We develop a multiscale strategy and a layer-stripping method to alleviate the local minimum problem of wave-equation dispersion inversion of Rayleigh waves, and improve the inversion robustness. We first invert the high-frequency and near-offset data for the shallow S-velocity model, and gradually incorporate the lower-frequency components of data with longer offsets to reconstruct the deeper regions of the model. We demonstrate the efficacy of this multiscale and layer-stripping method using synthetic and field Rayleigh-wave data.