P-002 SUMMARY FINITE-DIFFERENCE PERTURBATION METHOD FOR 3-D ANISOTROPIC MEDIA S. M. SOUKINA 1 D. GAJEWSKI 1 and B. M. KASHTAN 2 1 Institute of Geophysics University of Hamburg Bundesstr. 55 20146 Germany 2 St.Petersburg State University To compute the traveltime of seismic waves in a general anisotropic medium it is possible to use a perturbation approach which is based on approximating an anisotropic medium by a simpler analytically treatable reference medium. The isotropic reference medium works well for anisotropies of up to 10%. Some materials can exhibit a stronger anisotropy (e.g. shales). In this case it is possible to consider