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On the micromechanics of slip events in sheared, fluid‐saturated fault gouge
Author(s) -
Dorostkar Omid,
Guyer Robert A.,
Johnson Paul A.,
Marone Chris,
Carmeliet Jan
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl073768
Subject(s) - fault gouge , slip (aerodynamics) , drag , mechanics , fluid dynamics , discrete element method , micromechanics , granular material , geology , geotechnical engineering , slip factor , materials science , fault (geology) , composite material , thermodynamics , physics , seismology , impeller , composite number
We used a three‐dimensional discrete element method coupled with computational fluid dynamics to study the poromechanical properties of dry and fluid‐saturated granular fault gouge. The granular layer was sheared under dry conditions to establish a steady state condition of stick‐slip dynamic failure, and then fluid was introduced to study its effect on subsequent failure events. The fluid‐saturated case showed increased stick‐slip recurrence time and larger slip events compared to the dry case. Particle motion induces fluid flow with local pressure variation, which in turn leads to high particle kinetic energy during slip due to increased drag forces from fluid on particles. The presence of fluid during the stick phase of loading promotes a more stable configuration evidenced by higher particle coordination number. Our coupled fluid‐particle simulations provide grain‐scale information that improves understanding of slip instabilities and illuminates details of phenomenological, macroscale observations.