Integrated Workflow for Surface-wave Dispersion Inversion and Profiling

While surface-wave prospecting methods are classically applied for the one-dimensional (1D) estimation of shear (S-) wave velocities (Vs), two-dimensional (2D) profiling still requires implementing specific processing and inversion tools that are not yet widely available in the community. We present here a free and open-source tool performing surface-wave inversion and profiling (SWIP) in order to retrieve 2D lateral variations of Vs from typical seismic shot records. Windowing and stacking techniques are implemented to compute dispersion images with smooth lateral variations and enhanced signal-to-noise ratio. Dispersion curves are extracted for each window with an error in phase velocity taking into account the higher uncertainties at low frequency. These curves are then inverted for each window position using a Monte Carlo approach and a refraction tomography-based parameterization. Models matching the observed data within the error bars are selected to build a misfit-weighted final model and estimate the investigation depth. Finally, 1D models obtained for each window position are merged into a 2D Vs section.