Flattening common image gathers after full waveform inversion: the challenge of anisotropy estimation

It is often observed that common image gathers computed after FWI are not flat. This is due to an improper anisotropy estimation. We propose a new joint reflections-diving rays tomography to estimate anisotropy prior to FWI. It aims at both flattening the common image point gathers and matching the kinematics of the observed and synthetic diving waves. The method is successfully demonstrated on a real land 3D broadband dataset.