Improved subsalt tomography using RTM surface offset gathers

RTM surface offset gathers (SOG) contain subsalt events spanning the entire offset range (i.e., longer usable curvatures for tomography). RTM SOGs also have more reliable residual curvatures because each offset and azimuth group is migrated independently and does not interfere with the neighboring ones. RTM SOGs are more beneficial for full azimuth (FAZ) and ultra-long offset data.