Reverse searching procedure for real ray tracing in viscoelastic anisotropic media

The real ray tracing method is a much more realistic than the complex ray tracing method in a viscoelastic anisotropic media due to non-assumption of the complex space. It is the most critical step to determine the stationary slowness vector which offers the homogeneous ray-velocity vectors for seismic ray tracing in viscoelastic media. We proposal a general form of the cost function to obtain the slowness vector with a known ray direction, called reverse searching (RS) procedure that is a considerable challenge in the common forward searching (FS) procedure. In our method, the initial slowness angle for the cost function is found by interpolation from the curve of ray angles vs slowness angles calculated by the FS procedure. In the triplication range, the slowness angle corresponding the highest ray velocity is selected. As the result, the determined ray and slowness directions from the RS procedure well match those of the FS procedure. The difficulties of dealing with triplication and cusp of the qSV wavefronts has been circumvented in the RS procedure, and the problems of spurious solutions which were critical challenges in previous publications are also avoided.