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

Using ray perturbation theory, a linear relationship is derived that describes the first-order perturbation in slowness vectors due to elastic parameter and interface perturbations as well as to source and receiver position perturbations. For layered media, a propagator matrix, which has symplectic properties, is defined in Cartesian coordinates. The method is valid for heterogeneous isotropic or anisotropic media with interfaces, and allows the efficient calculation of Frechet derivatives of the polarization vectors. This makes it possible to use polarization 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 reference medium is a heterogeneous medium with elliptical anisotropy. A sensitivity study shows that the qP-wave polarization vectors provide information on the isotropic component of the slowness.