The Role of Grain Size and Effective Normal Stress on Localization and the Frictional Stability of Simulated Quartz Gouge

Bedford, John D ORCID: 0000-0002-2077-4797 and Faulkner, Daniel R ORCID: 0000-0002-6750-3775 (2021) The Role of Grain Size and Effective Normal Stress on Localization and the Frictional Stability of Simulated Quartz Gouge. Geophysical Research Letters, 48 (7).

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Official URL: http://dx.doi.org/10.1029/2020gl092023

Abstract

<jats:title>Abstract</jats:title><jats:p>For earthquakes to occur on tectonic faults deformation localizes onto discrete slip surfaces within the gouge material of the fault core. Here, we investigate how localization is promoted in quartz gouge, a material known to exhibit unstable stick‐slip behavior, by assessing the role of grain size and effective normal stress (<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl62165-math-0001.png" xlink:title="urn:x-wiley:00948276:media:grl62165:grl62165-math-0001" />) on microstructural evolution and frictional behavior. We observe stable sliding, slow‐slip instability, and stick‐slip with increasing displacement. We find that initially fine‐grained gouge and high <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl62165-math-0002.png" xlink:title="urn:x-wiley:00948276:media:grl62165:grl62165-math-0002" /> promotes unstable stick‐slip behavior, whereas slow‐slip is more prevalent at low <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl62165-math-0003.png" xlink:title="urn:x-wiley:00948276:media:grl62165:grl62165-math-0003" />. Microstructural analyses of the sheared gouges show that stick‐slip behavior occurs after localization of deformation on to discrete Y‐shears, which undergo a significant cataclastic grain size reduction relative to the bulk of the gouge, a process enhanced by high <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl62165-math-0004.png" xlink:title="urn:x-wiley:00948276:media:grl62165:grl62165-math-0004" />. Our results show that localization and instability are promoted by high effective normal stress and small grain size.</jats:p>

Item Type:	Article
Uncontrolled Keywords:	fault gouge, friction, localization, quartz, slow&#8208, slip, stick&#8208, slip
Divisions:	Faculty of Science and Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	22 Apr 2021 09:37
Last Modified:	04 Sep 2023 02:42
DOI:	10.1029/2020gl092023
Open Access URL:	https://agupubs.onlinelibrary.wiley.com/doi/10.102...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3120157