This project proposes to study the lateral heterogeneity and anisotropy in D; at the coremantle boundary and to account for the effects if D" structure in the analysis of inner core anisotropy from core-sensitive seismic data. Previous results have had success in constraining D' sturcture by modeling differential travel times of SH-SKS and SHdiff-SKS waves along corridors in the Pacific using a ray theoretical approach and finite difference computations. This proposal will expand this modeling effort in several directions, such as increasing coverage of the Pacific, peforming waveform modeling of the SV diff phase, and expanding an effort to model the effect of D" structure on PKP phases, particularly PKP (AB), which can be used to study inner core anisotropy. The results of this research will provide more accurate constraints on the heterogeneity in D' and the anisotropy of the inner core, and these seismic observations will ultimately be important for understanding deep mantle geodynamics and core dynmics.
