• 2D finite difference modelling
• genetic algorithm
• surface wave
• two-grid FWI

In this thesis a two-grid Full Waveform Inversion (FWI) of surface waves (Rayleigh) is proposed for the estimation of 1D and 2D models of shear wave velocity (Vs). One of the main objectives was the parametrization setting for the optimization technique considered. The aim was to obtain a tool capable of making qualitatively and quantitatively valid estimates of increasingly complicated models, within reasonable computational time.
Keeping an initial information content as limited as possible, three models with an increasing level of complexity were considered; this allowed us to test the robustness of our optimization process. Therefore, starting from a 1D synthetic case, good results are also achieved for a real-like model, improving the results of previous works. This has therefore made it possible to obtain information on the reliability of this type of inversion, giving indications on the acquisition geometry to be used, grid parameter setting, computation time and strategy to adopt in the inversion procedure (frequency marching and offset stripping) to obtain a good estimate of the characteristics of the subsoil.