Acoustic multiparameter Full-waveform Inversion of diving and reflected waves through a hierachical scheme

Most of the successful applications of FWI have been mainly driven by the information carried out by diving waves and subcritical reflections, as the classical formalism appears to be unable to exploit reflected waves to build the long-to-intermediate wavelengths of the velocity structure. Alternative approaches have been recently revisited to focus on short-spread reflections only using some prior knowledge of the reflectivity. The present study presents a unified formalism, which aims to update the low wavenumbers of the velocity model by joint inversion of the diving waves and the full reflected wavefield. A hierarchical scheme assuming a scale seperation is implemented to alternatively update the high-wavenumber impedance model through a non-linear migration-like approach and low wavenumber velocity model through our unified formulation.