Slab-plume interaction beneath the Pacific Northwest
Article first published online: 22 JUL 2010
Copyright 2010 by the American Geophysical Union.
Geophysical Research Letters
Volume 37, Issue 14, July 2010
How to Cite
2010), Slab-plume interaction beneath the Pacific Northwest, Geophys. Res. Lett., 37, L14305, doi:10.1029/2010GL043489., , , and (
- Issue published online: 22 JUL 2010
- Article first published online: 22 JUL 2010
- Manuscript Accepted: 16 JUN 2010
- Manuscript Revised: 4 JUN 2010
- Manuscript Received: 1 APR 2010
 The Pacific Northwest has undergone complex plate reorganization and intense tectono-volcanic activity to the east during the Cenozoic (last 65 Ma). Here we show new high-resolution tomographic images obtained using shear and compressional data from the ongoing USArray deployment that demonstrate first that there is a continuous, whole-mantle plume beneath the Yellowstone Snake River Plain (YSRP) and second, that the subducting Juan de Fuca (JdF) slab is fragmented and even absent beneath Oregon. The analysis of the geometry of our tomographic models suggests that the arrival and emplacement of the large Yellowstone plume had a substantial impact on the nearby Cascadia subduction zone, promoting the tearing and weakening of the JdF slab. This interpretation also explains several intriguing geophysical properties of the Cascadia trench that contrast with most other subduction zones, such as the absence of deep seismicity and the trench-normal fast direction of mantle anisotropy. The DNA velocity models are available for download and slicing at http://dna.berkeley.edu.