Angle Gathers for Gaussian Beam Migration

C018 Angle Gathers for Gaussian Beam Migration S.H. Gray* (CGGVeritas) SUMMARY Migrated common-image-gathers (CIG’s) are usually indexed by source-receiver offset measured along the Earth’s surface. However the recent popularity of migration by wavefield extrapolation has given rise to other types of CIG’s. In particular CIG’s indexed by opening angle at subsurface image locations have advantages over offset-indexed CIG’s: they allow more natural applications of tomography and waveequation migration velocity analysis and they allow amplitude analysis as a function of opening angle rather than offset (AVA vs. AVO). Another type of CIG occurring naturally in migrations that use a synthesized linear