Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska

Geophysical Research Letters
By:  and 

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Abstract

Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of Pn and Sn velocities. High Poisson's ratios at this depth (40-70 km), adjacent to the subducting slab, are attributed to melting of mantle-wedge peridotites, caused by fluids liberated from the subducting oceanic crust and sediments. Observations of high values of Poisson's ratio, beneath the Denali volcanic gap suggest that the mantle wedge contains melted material that is unable to reach the surface. We suggest that its inability to migrate through the overlying crust is due to increased compression in the crust at the northern apex of the curved Denali fault.

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Publication type Article
Publication Subtype Journal Article
Title Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska
Series title Geophysical Research Letters
DOI 10.1029/2001GL014088
Volume 29
Issue 16
Year Published 2002
Language English
Publisher Wiley
Contributing office(s) Geologic Hazards Science Center
Description 4 p.
First page 61-1
Last page 61-4
Country United States
State Alaska
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