Wavefield Tomography without Low Frequency Data

Waveform inversion (FWI) requires a good starting model and/or data at very low frequency (< 1Hz) for convergence. However, this is not a necessary condition, but an artifact of the objective function defined using differences of observed and simulated data. Image-domain tomographic methods using the same wavefields and wave-equations can converge to a reasonable solution from poor starting models and without long offset and/or low frequency data. Cascading image-domain and data-domain wavefield tomography eliminates the need for extremely low-frequency in the acquired data.