A second goal of this thesis is to overcome those limitations by designing a velocity analysis method based on wavefield extrapolation. A method of this type naturally inherits the characteristics of wavefield extrapolation, mainly robustness in presence of large and sharp velocity contrasts, band-limited model sensitivity and multipathing.
Conventional migration velocity analysis employs traveltime perturbations derived from moveout measurements on migrated common image gathers. In this dissertation, I modify this methodology to employ image perturbations , which can be defined either from moveout differences and/or from spatial focusing. Such analysis requires development of image perturbation methods (residual migration) and techniques for analysis of image quality (angle transformation).