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Title: Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method

Sheared granular layers undergoing stick-slip behavior are broadly employed to study the physics and dynamics of earthquakes. In this paper, a two-dimensional implementation of the combined finite-discrete element method (FDEM), which merges the finite element method (FEM) and the discrete element method (DEM), is used to explicitly simulate a sheared granular fault system including both gouge and plate, and to investigate the influence of different normal loads on seismic moment, macroscopic friction coefficient, kinetic energy, gouge layer thickness, and recurrence time between slips. In the FDEM model, the deformation of plates and particles is simulated using the FEM formulation while particle-particle and particle-plate interactions are modeled using DEM-derived techniques. The simulated seismic moment distributions are generally consistent with those obtained from the laboratory experiments. In addition, the simulation results demonstrate that with increasing normal load, (i) the kinetic energy of the granular fault system increases; (ii) the gouge layer thickness shows a decreasing trend; and (iii) the macroscopic friction coefficient does not experience much change. Analyses of the slip events reveal that, as the normal load increases, more slip events with large kinetic energy release and longer recurrence time occur, and the magnitude of gouge layer thickness decrease also tendsmore » to be larger; while the macroscopic friction coefficient drop decreases. Finally, the simulations not only reveal the influence of normal loads on the dynamics of sheared granular fault gouge, but also demonstrate the capabilities of FDEM for studying stick-slip dynamic behavior of granular fault systems.« less
Authors:
ORCiD logo [1] ;  [1] ; ORCiD logo [1] ;  [2] ; ORCiD logo [1] ; ORCiD logo [1] ;  [3] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Nevada, Reno, NV (United States). Dept. of Physics
  3. Swiss Federal Inst. of Technology Zurich (ETH Zurich) (Switzerland). Dept. of Mechanical and Process Engineering
Publication Date:
Report Number(s):
LA-UR-18-20365
Journal ID: ISSN 2169-9313
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Solid Earth
Additional Journal Information:
Journal Name: Journal of Geophysical Research. Solid Earth; Journal ID: ISSN 2169-9313
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; LANL Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; stick-slip; granular material; fault gouge; combined finite-discrete element method (FDEM); earthquake simulation
OSTI Identifier:
1457309

Gao, Ke, Euser, Bryan J., Rougier, Esteban, Guyer, Robert A., Lei, Zhou, Knight, Earl E., Carmeliet, Jan, and Johnson, Paul A.. Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method. United States: N. p., Web. doi:10.1029/2018JB015668.
Gao, Ke, Euser, Bryan J., Rougier, Esteban, Guyer, Robert A., Lei, Zhou, Knight, Earl E., Carmeliet, Jan, & Johnson, Paul A.. Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method. United States. doi:10.1029/2018JB015668.
Gao, Ke, Euser, Bryan J., Rougier, Esteban, Guyer, Robert A., Lei, Zhou, Knight, Earl E., Carmeliet, Jan, and Johnson, Paul A.. 2018. "Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method". United States. doi:10.1029/2018JB015668.
@article{osti_1457309,
title = {Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method},
author = {Gao, Ke and Euser, Bryan J. and Rougier, Esteban and Guyer, Robert A. and Lei, Zhou and Knight, Earl E. and Carmeliet, Jan and Johnson, Paul A.},
abstractNote = {Sheared granular layers undergoing stick-slip behavior are broadly employed to study the physics and dynamics of earthquakes. In this paper, a two-dimensional implementation of the combined finite-discrete element method (FDEM), which merges the finite element method (FEM) and the discrete element method (DEM), is used to explicitly simulate a sheared granular fault system including both gouge and plate, and to investigate the influence of different normal loads on seismic moment, macroscopic friction coefficient, kinetic energy, gouge layer thickness, and recurrence time between slips. In the FDEM model, the deformation of plates and particles is simulated using the FEM formulation while particle-particle and particle-plate interactions are modeled using DEM-derived techniques. The simulated seismic moment distributions are generally consistent with those obtained from the laboratory experiments. In addition, the simulation results demonstrate that with increasing normal load, (i) the kinetic energy of the granular fault system increases; (ii) the gouge layer thickness shows a decreasing trend; and (iii) the macroscopic friction coefficient does not experience much change. Analyses of the slip events reveal that, as the normal load increases, more slip events with large kinetic energy release and longer recurrence time occur, and the magnitude of gouge layer thickness decrease also tends to be larger; while the macroscopic friction coefficient drop decreases. Finally, the simulations not only reveal the influence of normal loads on the dynamics of sheared granular fault gouge, but also demonstrate the capabilities of FDEM for studying stick-slip dynamic behavior of granular fault systems.},
doi = {10.1029/2018JB015668},
journal = {Journal of Geophysical Research. Solid Earth},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {6}
}