Influence of weakening minerals on ensemble strength and slip stability of faults

Chaoyi Wang, Derek Elsworth, Yi Fang

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We explore the impact of phyllosilicate (weak but velocity strengthening) in a majority tectosilicate (strong but velocity weakening) matrix on bulk shear strength and slip stability of faults. Numerical simple shear experiments using a distinct element model (DEM) are conducted on both uniform mixtures of quartz and talc analogs and on textured mixtures consisting of a talc layer embedded in a quartz matrix. The mechanical response of particles is represented by a linear elastic contact model with a slip-weakening constitutive relation representing the essence of rate-state friction. The weight percentage of the talc in the uniform mixtures and the relative thickness of the talc layer in the textured mixtures are varied to investigate the transitional behavior of shear strength and slip stability. Specifically, for uniform mixtures, ~50% reduction on bulk shear strength is observed with 25% talc present, and a dominant influence of talc occurs at 50%; for textured mixtures, a noticeable weakening effect is shown at a relative layer thickness of 1 particle, ~50% shear strength reduction is observed with 3-particles, and a dominant influence occurs at 5 particles. In terms of slip stability, a transition from velocity weakening to velocity strengthening is observed with 10% to 25% talc present in the uniform mixtures or with 3 particles to 5 particles in the textured mixtures. In addition, further analysis suggests that quartz has a high tendency toward dilation, potentially promoting permeability; while talc dilates with increased slip rate but compacts rapidly when slip rate is reduced, potentially destroying permeability. The simulation results match well with previous laboratory observations.

Original languageEnglish (US)
Pages (from-to)7090-7110
Number of pages21
JournalJournal of Geophysical Research: Solid Earth
Volume122
Issue number9
DOIs
StatePublished - Sep 2017

Fingerprint

Talc
talc
Minerals
slip
minerals
shear strength
mineral
Shear strength
Quartz
quartz
slip rate
permeability
tectosilicate
matrix
dilation
phyllosilicate
matrices
tendencies
friction
analogs

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

@article{2ad8cd9959514261a7234fbd7d2f3985,
title = "Influence of weakening minerals on ensemble strength and slip stability of faults",
abstract = "We explore the impact of phyllosilicate (weak but velocity strengthening) in a majority tectosilicate (strong but velocity weakening) matrix on bulk shear strength and slip stability of faults. Numerical simple shear experiments using a distinct element model (DEM) are conducted on both uniform mixtures of quartz and talc analogs and on textured mixtures consisting of a talc layer embedded in a quartz matrix. The mechanical response of particles is represented by a linear elastic contact model with a slip-weakening constitutive relation representing the essence of rate-state friction. The weight percentage of the talc in the uniform mixtures and the relative thickness of the talc layer in the textured mixtures are varied to investigate the transitional behavior of shear strength and slip stability. Specifically, for uniform mixtures, ~50{\%} reduction on bulk shear strength is observed with 25{\%} talc present, and a dominant influence of talc occurs at 50{\%}; for textured mixtures, a noticeable weakening effect is shown at a relative layer thickness of 1 particle, ~50{\%} shear strength reduction is observed with 3-particles, and a dominant influence occurs at 5 particles. In terms of slip stability, a transition from velocity weakening to velocity strengthening is observed with 10{\%} to 25{\%} talc present in the uniform mixtures or with 3 particles to 5 particles in the textured mixtures. In addition, further analysis suggests that quartz has a high tendency toward dilation, potentially promoting permeability; while talc dilates with increased slip rate but compacts rapidly when slip rate is reduced, potentially destroying permeability. The simulation results match well with previous laboratory observations.",
author = "Chaoyi Wang and Derek Elsworth and Yi Fang",
year = "2017",
month = "9",
doi = "10.1002/2016JB013687",
language = "English (US)",
volume = "122",
pages = "7090--7110",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "9",

}

Influence of weakening minerals on ensemble strength and slip stability of faults. / Wang, Chaoyi; Elsworth, Derek; Fang, Yi.

In: Journal of Geophysical Research: Solid Earth, Vol. 122, No. 9, 09.2017, p. 7090-7110.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Influence of weakening minerals on ensemble strength and slip stability of faults

AU - Wang, Chaoyi

AU - Elsworth, Derek

AU - Fang, Yi

PY - 2017/9

Y1 - 2017/9

N2 - We explore the impact of phyllosilicate (weak but velocity strengthening) in a majority tectosilicate (strong but velocity weakening) matrix on bulk shear strength and slip stability of faults. Numerical simple shear experiments using a distinct element model (DEM) are conducted on both uniform mixtures of quartz and talc analogs and on textured mixtures consisting of a talc layer embedded in a quartz matrix. The mechanical response of particles is represented by a linear elastic contact model with a slip-weakening constitutive relation representing the essence of rate-state friction. The weight percentage of the talc in the uniform mixtures and the relative thickness of the talc layer in the textured mixtures are varied to investigate the transitional behavior of shear strength and slip stability. Specifically, for uniform mixtures, ~50% reduction on bulk shear strength is observed with 25% talc present, and a dominant influence of talc occurs at 50%; for textured mixtures, a noticeable weakening effect is shown at a relative layer thickness of 1 particle, ~50% shear strength reduction is observed with 3-particles, and a dominant influence occurs at 5 particles. In terms of slip stability, a transition from velocity weakening to velocity strengthening is observed with 10% to 25% talc present in the uniform mixtures or with 3 particles to 5 particles in the textured mixtures. In addition, further analysis suggests that quartz has a high tendency toward dilation, potentially promoting permeability; while talc dilates with increased slip rate but compacts rapidly when slip rate is reduced, potentially destroying permeability. The simulation results match well with previous laboratory observations.

AB - We explore the impact of phyllosilicate (weak but velocity strengthening) in a majority tectosilicate (strong but velocity weakening) matrix on bulk shear strength and slip stability of faults. Numerical simple shear experiments using a distinct element model (DEM) are conducted on both uniform mixtures of quartz and talc analogs and on textured mixtures consisting of a talc layer embedded in a quartz matrix. The mechanical response of particles is represented by a linear elastic contact model with a slip-weakening constitutive relation representing the essence of rate-state friction. The weight percentage of the talc in the uniform mixtures and the relative thickness of the talc layer in the textured mixtures are varied to investigate the transitional behavior of shear strength and slip stability. Specifically, for uniform mixtures, ~50% reduction on bulk shear strength is observed with 25% talc present, and a dominant influence of talc occurs at 50%; for textured mixtures, a noticeable weakening effect is shown at a relative layer thickness of 1 particle, ~50% shear strength reduction is observed with 3-particles, and a dominant influence occurs at 5 particles. In terms of slip stability, a transition from velocity weakening to velocity strengthening is observed with 10% to 25% talc present in the uniform mixtures or with 3 particles to 5 particles in the textured mixtures. In addition, further analysis suggests that quartz has a high tendency toward dilation, potentially promoting permeability; while talc dilates with increased slip rate but compacts rapidly when slip rate is reduced, potentially destroying permeability. The simulation results match well with previous laboratory observations.

UR - http://www.scopus.com/inward/record.url?scp=85029391076&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85029391076&partnerID=8YFLogxK

U2 - 10.1002/2016JB013687

DO - 10.1002/2016JB013687

M3 - Article

AN - SCOPUS:85029391076

VL - 122

SP - 7090

EP - 7110

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 9

ER -