S-velocity Structure

Long Business Description

The tectonic diversity of the North American continent makes it an ideal region to investigate the structure and dynamics of the continental upper mantle. Investigations of timely geophysical questions, such as the relation to geological age of the variations in the lithospheric thickness, the relation of upper-mantle anisotropy to present day asthenospheric flow and past tectonic events, the nature and strength of the lithosphere/asthenosphere coupling and the driving mechanisms of plate motions, are contingent upon obtaining high-resolution 3-D tomographic models of the isotropic and anisotropic mantle structure of the continent.


Updated isotropic S velocity (a), radial anisotropy (b) and azimuthal anisotropy (c and d) model of the North America upper mantle. Horizontal resolution is 200-km, 400-km, and 400-km for (a), (b) and (c), respectively. (c) and (d) show two azimuthal anisotropy models by surface waveforms only and by surface waveforms and SKS splits, respectively.
Updated isotropic S velocity (a), radial anisotropy (b) and azimuthal anisotropy (c and d) model of the North America upper mantle. Horizontal resolution is 200-km, 400-km, and 400-km for (a), (b) and (c), respectively. (c) and (d) show two azimuthal anisotropy models by surface waveforms only and by surface waveforms and SKS splits, respectively.