Beall, Adam, Fagereng, Ake and Ellis, Susan
2019.
Strength of strained two-phase mixtures: Application to rapid creep and stress amplification in subduction zone mélange.
Geophysical Research Letters
46
(1)
, pp. 169-178.
10.1029/2018GL081252
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Abstract
Aseismic creep may occur by distributed deformation in mélange shear zones comprising weak matrix and stronger clast materials. Slow slip events or steady tectonic displacement can be distributed over <100‐m thick shear zones if weak matrix controls bulk shear zone deformation. We use 2‐D numerical models to quantify the rheology of moderately strained (shear strain <1.75) mélange for various volumetric proportions of competent clasts. Mélange deformation with <50% clasts is matrix dominated and can accommodate steady creep. At higher clast proportions mélange viscosity increases more than tenfold after small strains, because strong clasts interact and form force chains. Clast shear stress is amplified above the imposed shear stress, by a factor of <14 where force chains develop. Slow slip events may occur due to a temporary absence of force chains, while localized regions of high shear stress generate coincident fracturing and potentially tremor events.
Item Type: | Article |
---|---|
Date Type: | Publication |
Status: | Published |
Schools: | Earth and Ocean Sciences Advanced Research Computing @ Cardiff (ARCCA) |
Subjects: | Q Science > QE Geology |
Publisher: | American Geophysical Union (AGU) |
ISSN: | 0094-8276 |
Date of First Compliant Deposit: | 30 January 2019 |
Date of Acceptance: | 27 December 2018 |
Last Modified: | 03 May 2020 15:02 |
URI: | http://orca.cf.ac.uk/id/eprint/118402 |
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