A fast and robust two‐point ray tracing method in layered vertical transversely isotropic media with strong anisotropy

Abstract

A fast and robust two‐point ray tracing method was developed for layered vertical transversely isotropic media with strong anisotropy. Utilizing the Christoffel slowness equation, a novel generalized dimensionless ray parameter, , modified from the ray parameter (horizontal slowness), was proposed to efficiently and simultaneously determine the ray paths and travel times for direct and reflected quasi‐P, quasi‐SV and quasi‐SH waves. The Newton optimization algorithm was employed to solve the nonlinear offset equation accurately, resulting in rapid convergence to the true value. The inferred analytical equations show that the generalized ray parameter stabilizes the inversion process at large offsets. Additionally, a piecewise function was introduced to enhance the initial value estimation and calculation efficiency. The numerical results demonstrate that this novel approach can reduce the iteration error to 10−10 m in less than three iterations. Monte Carlo simulations further validated the effectiveness of the method for inferring the true ray paths at various offsets within complex velocity models. Furthermore, the method can address the triplication issue in quasi‐SV waves and exhibit robustness in strong‐layered vertical transversely isotropic media.