SENSITIVITY OF QP-WAVE TRAVEL-TIMES AND POLARIZATION VECTORS TO HETEROGENEITY, ANISOTROPY AND INTERFACES

Using ray perturbation theory, a linear relationship is derived that d escribes the first-order perturbation in slowness vectors due to elast ic parameter and interface perturbations as well as to source and rece iver position perturbations. For layered media, a propagator matrix, w hich has symplectic properties, is defined in Cartesian coordinates. T he method is valid for heterogeneous isotropic or anisotropic media wi th interfaces, and allows the efficient calculation of Frechet derivat ives of the polarization vectors. This makes it possible to use polari zation data in tomographic inversion. Explicit integral expressions of the Frechet derivatives of the traveltime and the polarization vector are given for the qP wave in a transverse isotropic medium. The refer ence medium is a heterogeneous medium with elliptical anisotropy. A se nsitivity study shows that the qP-wave polarization vectors provide in formation on the isotropic component of the slowness.