We propose a perturbation-based approximation for P- and S-wave traveltime in a transversely isotropic medium with a vertical symmetry axis (VTI). The perturbation coefficients in this approximation are derived directly from the implicit parametric offset-traveltime equation. The comparison with the generalized moveout approximation (GMA) for both P-and S-waves are described in the numerical examples. Our proposed approximation shows higher accuracy than that of the GMA counterpart for P- and S-waves. The error sensitivity of P- and S-waves in vertical velocity ratio and the value of the anellipticity parameter are also analyzed to examine the influence of these factors. Besides, we investigate the anisotropy estimation through two approximations for P- and S-waves and find that our proposed perturbation method results in a high accuracy, which can contribute to improving the quality of the data processing greatly
Note: This paper was accepted into the Technical Program but was not presented at IMAGE 2022 in Houston, Texas.
