3D VTI traveltime tomography for near-surface imaging

Abstract

Seismic first arrivals that propagate in the near surface area are affected by velocity anisotropy. With VTI assumption for the media, we develop a grid-based qP wave traveltime tomography method to invert Thomsen parameters, including  and at each grid point in the shallow area. In numerical experiments, we fix the symmetry axis velocity V p0 , inverting only  and . For single-parameter inversion, we invert  and  respectively, and for twoparameter inversion, we invert  and  simultaneously. Results indicate that  is better resolved than  from inverting the first arrivals.