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High-resolution imaging of continental tectonics in the mantle beneath the United States, through the combination of USArray data sets
  • Heather Bedle,
  • Xiaoting Lou,
  • Suzan van der Lee
Heather Bedle
University of Oklahoma

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Xiaoting Lou
Northwestern University
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Suzan van der Lee
Northwestern University
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Abstract

A comprehensive North American upper mantle seismic-tomographic model, NA13, was inferred from a combination of several decades of seismic data from early North American seismic models and USArray data. This data-driven modeling inverted a combination of regional waveform misfits, teleseismic S delay times, and constraints on Moho depths. The joint inversion model combines the contrasting and overlapping resolving power of the different data sets, and demonstrates enhanced resolution over regional models created with a single geophysical dataset. Resolution in the upper mantle is achieved on the scale of ~100km, although travel time delay studies suggest that anomalies in parts of the western United States are smaller. In NA13, velocities beneath the Yellowstone plume are low enough to require the presence of partial melt. NA13 also models a variety of smaller scale velocity variations beneath the Central and Eastern United States that reveal remnant velocity anomalies in the upper mantle from Mesozoic and Cenozoic tectonics.