f 3D Ray Tracing by the Fermat's Principle in Irregular Grids

Ray tracing is often used as a part of algorithms for seismic inversion, and so its main features are chosen according to the number and type of parameters to be estimated. Vesnaver (1994) showed that irregular grids can improve significantly the stability and reliability of traveltime inversion. So we developed a ray tracing method based on the Fermat's principle of minimum time, able to compute the ray path and traveltime of transmitted, reflected, refracted and diffracted waves in 3D irregular grids.