Velocities in imaging and stratigraphic inversion: new opportunities for integration

For long in seismic imaging, velocity model building and depth migration/inversion have produced information on the subsurface velocity model with no overlap in terms of resolved vertical wavelengths. The not covered wavelengths, among which the famous mid frequency gap, had then to be recovered in stratigraphic inversion by external information such as borehole data. The progresses in terms of acquisitions (long offset and low frequency) and imaging tools put us now in the situation of an overlap between all these processing/imaging/inversion approaches. FWI provides for example a velocity model building tool that covers potentially the full range of vertical frequencies in the area investigated by recorded diving waves. High resolution tomography from its side reaches vertical resolutions up to 6 Hz overlapping the resolution that can be obtained from depth migration and then stratigraphic inversion with low frequency data (down to 2.5 Hz). This new status has motivated investigations about improved ways of integrating these sources of information. We review here several of these attempts that allow taking advantage of the various approaches for the benefits of reliability and interpretability of the results. The estimation of uncertainties in ray based tomography is for example a precious add on for assessing the reliability of the final result of the imaging/inversion workflow.