Publication Date:
2022-05-25
Description:
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 38 (2011): L13308, doi:10.1029/2011GL047705.
Description:
In the forearc mantle wedge, the thermal field depends strongly on slab-driven mantle wedge flow. The flow is in turn affected by the thermal field via the temperature dependence of mantle rheology. Using thermal modeling, we show that the nonlinear feedback between the thermal and flow fields always leads to complete stagnation of the mantle wedge over a shallow, weakened part of the slab-mantle interface and an abrupt onset of mantle flow further down-dip. The abrupt increase in flow velocity leads to a sharp thermal transition from a cold stagnant to a hot flowing part of the wedge. This sharp thermal transition is inherent to all subduction zones, explaining a commonly observed sharp arc-ward increase in seismic attenuation.
Description:
This research was partially supported by
National Science Foundation through a MARGINS postdoctoral fellowship
(NSF OCE‐0840800) and by Natural Environment Research Council.
Keywords:
Mantle rheology
;
Mantle wedge
;
Seismic attenuation
;
Subduction zone
;
Thermal structure
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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