Tomographic Full Waveform Inversion (TFWI) by Extending the Velocity Model along the Time-lag Axis

The extension of the velocity model along the subsurface-offset axes enables to define a tomographic full waveform inversion that converges robustly towards high-resolution velocity models. However the resulting numerical algorithms are extremely expensive and their performance is uncertain when transmitted events (e.g. diving waves) are present in the data. We discuss the advantages of extending the velocity model along the time-lag axis instead of the subsurface offsets. This extension leads to a linearization of the wave equation that overcomes the well-known limitation of the first-order Born approximation to model large time shifts in the data.