Least-squares reverse-time migration in VTI media using a T-distribution-based misfit function

Abstract Anisotropy of subsurface media can affect the seismic wave travel time estimates, and then imaging target regions. To calibrate effect anisotropy, a VTI (transverse isotropy with vertical symmetry axis) least-squares reverse-time migration (LSRTM) algorithm is used. However, if data contains noise especially outliers, high-quality images cannot be produced by LSRTM based on an L2 norm. Considering that Student's t-distribution has better robustness than norm, this study derives VTI-LSRTM (T-VTI-LSRTM) misfit function. The plane-wave encoding introduced into T-VTI-LSRTM to improve computational efficiency. We conduct numerical tests using complex models illustrate effectiveness adaptability method. sensitivity analysis velocity anisotropy parameters demonstrate have distinct results, in which strongest, epsilon parameter delta weakest.