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ID 30897
file
creator
Tagawa, Michio
Iwase, Yasuyuki
subject
Stagnant slab
Subduction
Mantle convection
Rheology
Numerical modeling
NDC
Earth sciences. Geology
abstract
We performed a numerical study to understand the dynamical mechanism controlling the formation and avalanche of a stagnant slab using two-dimensional dynamical models of the integrated plate-mantle system with freely movable subducting and overriding plates. We examined slab rheology as a mechanism for producing various styles of stagnating or penetrating slabs that interact with the 410-km and 660-km phase transitions. The simulated results with the systematically changed rheological parameters are interpreted using a simple stability analysis that includes the forces acting on the stagnant slab. Slab plasticity that memorizes the shape produced by past deformation generates slab stagnation at various depths around the 660-km phase transition. The slab stagnates even beneath the 660-km phase boundary, with a gentle Clapeyron slope. Feedbacks between trench backward migration and slab deformation promote each other during the slab stagnation stage. Slab viscosity also determines the final state of the subducted slab, that is, it continues stagnation or initiates penetration. A low viscosity slab can finally penetrate into the lower mantle because the growth time of the Rayleigh–Taylor instability is shorter. After the avalanche, the direction of the trench migration changes depending on the lower mantle slab viscosity.
journal title
Physics of the Earth and Planetary Interiors
volume
Volume 183
issue
Issue 1-2
start page
309
end page
320
date of issued
2010-11
publisher
Elsevier Science BV
issn
0031-9201
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2010 Published by Elsevier B.V.
relation url
department
Graduate School of Science



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