Acoustic nonlinear amplitude versus angle inversion and data-driven depth imaging in stratified media derived from inverse scattering approximations

This paper extends from acoustic to elastic the theory for nonlinear direct amplitude versus angle (AVA) inversion and data-driven depth imaging for a depth-variable medium published by the authors in this journal. The method which is derived by direct inversion of the forward model of elastic single compressional wave scattering requires no information of the velocities and density, except for the velocities and density of the uppermost layer which is the acoustic reference medium where the source and receiver are situated at finite distance above the elastic scattering medium. The vertically varying velocities and density of the scattering medium are estimated in a data-driven manner solely from the angle- and depth-dependent Born potential depth profile computed by constant-velocity imaging.