This research is to use regional broadband data to study Pn and Sn propagation in North America, initially concentrating on the western United States. The regional phases Pn and Sn are sensitive to structure in the uppermost mantle, providing information that is difficult to obtain from other seismic phases on the degree and nature of heterogeneity and anisotropy in the subcrustal lithosphere. The work will investigate the questions of frequency- dependent travel times and azimuthal anisotropy, both of which address the larger question of the small-scale structure of the continental upper mantle. This funding is under the NSF Research Planning Grant program for women.
