Nonlinear Isotropic Elastic Multiparameter Inversion with Multicomponent P-wave Second-order Born Approximation

Abstract

Summary An asymptotic quadratic true-amplitude inversion method for isotropic elastic P waves is proposed to invert medium parameters. The multicomponent P-wave scattered wavefield is computed based on a forward relationship using second-order Born approximation and corresponding high-frequency ray theoretical methods. Within the local double scattering mechanism, the P-wave transmission factors are elaborately calculated, which results in the radiation pattern for P-waves scattering being a quadratic combination of the density and Lame’s moduli perturbation parameters. After introducing classical backprojection operators, we obtain an approximate solution of the inverse problem by solving a quadratic non-linear system. Numerical tests demonstrate that our quadratic inversion can accurately improve the restored perturbation parameters for strong perturbations, compared with the P-wave single-scattering inversion method.