Thermal and water content structures of the North American upper mantle inferred from seismic tomography Fei wang
This work seeks to deduce the spatial distribution of water in the mantle transition zone beneath North America using data from regional seismic studies. I have written a Python program (HyMaTZ) that (1) use literature data from mineral physics experiments and theory as the database for developing correlations to model the effects of the defect structure of the minerals on their physical properties that affect seismic velocities and (2) calculate thermodynamic effects (including phase(s) and phase transition(s) present) due to the existent temperature, iron content, and water content structures in the mantle. I use this program to calculate synthetic seismic velocity profiles, and compare the synthetic and measured seismic velocities, including seismic wave speeds and discontinuities in the profile, to do inversion by forward modeling. The preliminary result indicates that the weak S velocity anomaly beneath the U.S. east coast is probably due to a hydrous mantle.