f Finite-difference traveltime and reflection seismics - modelling and inversion

Finite-difference traveltime methods are used nowadays in a large domgin of applications. Their easy use and fastness, plus the robustness of some algorithms, make them attractive despite of the first arrival criterium, which may indeed be bypassed. They are therefore interesting simple tools which may be used for quick studies, in order to define parameters for following processes. Examples are presented in reflection seismics, both for modeling and inversion. We used the method of Podvin & Lecomte (1991) because of its robustness. This method is also developped in 3D, and for anisotropic media.