Abstract: The tomographic inversion of near-surface velocities is one of effective approaches to improve the accuracy of static correction in surface-complicated area. Based on the basic principle of tomographic inversion, a method for layer-by-layer extension with travel time linear interpolation is introduced in ray tracing, which helps to get more accurate ray-paths. Instead of using conventional mathematical ray-path, the conception of Fresnel zone is used to establish the inversion equations, which enhances the resistance to the error originated from first-break picking. The advantage of the method is proved both by theoretical calculation and real application.

Key words: ray tracing, tomography inversion, static correction, Fresnel zone