Subsurface Focusing Measurement of Diving Waves and its Application to Reflection Tomography

The classical full waveform inversion measures the traveltime residual of diving waves on the acquisition surface. This paper shows, based on the focusing principle, this residual can be also measured in the subsurface via reverse time migration. The objective function for the velocity inversion is posed entirely in the subsurface domain by penalizing the defocusing induced from both reflections and refractions. The optimization algorithm on the reverse time migration platform is described. The robustness of the method is demonstrated with a series of synthetic examples.