Elastic Envelope Inversion

We developed the elastic envelope inversion method. The envelope of the wavefields carries ultra low frequency information which can be used to recover the large-scale component of the model, and the initial model dependence of waveform inversion can be reduced. We derived the misfit function and the corresponding gradient operator for elastic envelope inversion. Numerical tests using synthetic data for the Marmousi II model proved the validity and feasibility of the proposed approach. The inverted p-wave velocity and s-wave velocity from the combined (EI+WI) envelope inversion plus waveform inversion indicated that it can deliver much improved results compared with regular elastic full waveform inversion.