Tomographic Full Waveform Inversion (TFWI) by Successive Linearizations and Scale Separations

Tomographic Full waveform inversion (TFWI) provides a framework to invert the seismic data that is immune to cycle-skipping problems by extending the velocity model. However, this extension makes the propagation considerably more expensive because each multiplication by velocity becomes a convolution. We provide an alternative formulation which computes the backscattering and the forward scattering components of the gradient separately. The inversion setup includes two steps that maintain the high resolution results of TFWI. First, the linearized residual are updated in a nested inversion scheme. Second, the two components of the gradient are first mixed and then separated based on a Fourier domain scale separation to allow for a fully simultaneous inversion of model scales.