Full wavefield modeling and inversion for laterally varying media

Joint migration inversion (JMI) has been implemented with the implicit assumption that the medium parameters are only smoothly laterally varying. We extend JMI such that its modeling algorithm is capable of properly handling strong lateral medium variations. The extension is made by computing propagation and scattering operators using modal expansion. In order to simulate wave propagation in unbounded media, a perfectly matched layer (PML) is implemented. The resulting propagation and scattering operators are not limited by angle of propgation. The extended modeling algorithm is then used for Full Wavefield Migration (FWM) and JMI, which is also extended using a preconditioned conjugate gradient scheme. A numerical example shows that the proposed JMI algorithm is capable of recovering not only the macro-model but also the micro-model. In the numerical example, a velocity anomaly, embedded in a layered model, is recovered with high resolution, along with the accompanying image.