A Newton-CG Method for Full-Waveform Inversion in a Coupled Solid-Fluid System

We present a Newton-CG method for full-waveform seismic inversion. Our method comprises the adjoint-based computation of the gradient and Hessian-vector products of the reduced problem and a preconditioned conjugate gradient method to solve the Newton system in matrix-free fashion. A trust-region globalization strategy and a multi-frequency inversion approach are applied. The governing equations are given by a coupled system of the acoustic and the elastic wave equation for the numerical simulation of wave propagation in solid and fluid media. We show numerical results for the application of our method to marine geophysical exploration.