Brantut, N;
Stefanou, I;
Sulem, J;
(2017)
Dehydration-induced instabilities at intermediate depths in subduction zones.
Journal of Geophysical Research: Solid Earth
, 122
(8)
pp. 6087-6107.
10.1002/2017JB014357.
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Abstract
We formulate a model for coupled deformation and dehydration of antigorite, based on a porosity-dependent yield criterion and including shear-enhanced compaction. A pore pressure and compaction instability can develop when the net volume change associated with the reaction is negative, i.e., at intermediate depth in subduction zones. The instability criterion is derived in terms of the dependence of the yield criterion on porosity: if that dependence is strong, instabilities are more likely to occur. We also find that the instability is associated with strain localization, over characteristic length scales determined by the hydraulic diffusivity, the elasto-plastic parameters of the rock, and the reaction rate. Typical lower bounds for the localization length are of the order of 10 to 100 for antigorite dehydration and deformation at 3 GPa. The fluid pressure and deformation instability is expected to induce stress buildup in the surrounding rocks forming the subducted slab, which provides a mechanism for the nucleation and propagation of intermediate-depth earthquakes.
| Type: | Article |
|---|---|
| Title: | Dehydration-induced instabilities at intermediate depths in subduction zones |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/2017JB014357 |
| Publisher version: | https://doi.org/10.1002/2017JB014357 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Science & Technology, Physical Sciences, Geochemistry & Geophysics, FLUID-FLOW, ANTIGORITE SERPENTINITE, DEFORMATION MECHANISMS, REACTION-KINETICS, COMPACTION BANDS, PRESSURE, DUCTILE, CREEP, ROCKS, TRANSITION |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10025143 |
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