Elastic Reverse-time Migration and Velocity Analysis Using Multicomponent Geophone Data

Abstract

Summary In this paper, we deal with the problem of P-P and P-S imaging and velocity analysis using multicomponent geophone data and elastic reverse-time migration. The case of elastic reverse-time migration, and that of elastic imaging in general is more complicated than the acoustic counterparts by the existence of P- and S-wave modes. This requires an imaging condition able to distinguish apart the different scattering events. Another important requirement is the ability to build accurate P-wave (vp) and S-wave (vs) velocity models. The difficulties associated with obtaining good quality images of P-S reflections results in that, even if multicomponent data is available, it is seldom that the horizontal components are actually used for subsurface imaging, analysis and interpretation. Here, we present imaging conditions capable of imaging P-P and P-S scattering events using all geophone components. The migrated images are then used in an automatic stackpower maximisation procedure to estimate optimal vp and vs migration velocity models. We test the methodology in 2D synthetic and field datasets.