Anisotropic models are recognized as more realistic representations
of the subsurface in complex geological environments. These
models are widely needed by many kinds of migration and interpretation
schemes. However, anisotropic model building is still a challenging
problem in the industry. In this paper, we propose an approach to
building anisotropic models from surface seismic data based on the
theory of Wave-Equation Migration Velocity Analysis (WEMVA). Because of the ambiguity
between depth and Thomsen parameter
, we parametrize our model space using only NMO velocity
(
) and the anellipticity parameter
. We tested the
anisotropic WEMVA on a shallow part of the Hess synthetic VTI model. The results show that
anisotropic WEMVA is effective in resolving some of the anisotropic
perturbation. However, a unique solution to the inversion requires
additional constraining information.