Abstract

This talk will summarize a new radially anisotropic seismic model of the crustal and upper mantle structure of the western United States from adjoint waveform tomography. The model reveals known structure of this large region but in a new holistic image with finer resolution than previous studies.  The model reveals high shear wavespeeds at depth associated with subducting slab fragments (Gorda, Juan de Fuca, Isabella Anomaly) and a piece of the Monterey microplate attached to the Pacific Plate.  Low shear wavespeeds associated with magmatism are seen in the crust beneath the Clear Lake Volcanic Field, Yellowstone Hotspot and Rio Grande Rift and clearly connect with the upper mantle.