Data from the PASSCAL NOMAD Experiment, Southern New York

STS-2s were deployed at four sites in southern New York (VASR, WIND, WICK, and SCCC) in June, 1997. The instruments at VASR and WIND were moved to UCON and UHRT in October, 1998, and the experiment ended in February, 1999. Data was recorded continuously at 20 sps and 1 sps. Preliminary results: Shear-wave splitting measurements reveal variations in upper mantle anisotropy over length scales of roughly 50 km. These results, combined with other eastern North American shear-wave splitting measurements and inversion of Rayleigh wave data, are best explained by a combination of asthenospheric flow and lithospheric deformation. Splitting in core-diffracted shear phases requires strong variations in anisotropy near the core-mantle boundary beneath the Pacific.