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

Abstract

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:

Gao, Ke  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0908-7056"

Euser, Bryan J. ^[1]; Rougier, Esteban  ^[1];

• Search DOE PAGES for author "Rougier, Esteban"
• Search DOE PAGES for ORCID "0000-0002-4624-2844"

Guyer, Robert A. ^[2]; Lei, Zhou  ^[1];

• Search DOE PAGES for author "Lei, Zhou"
• Search DOE PAGES for ORCID "0000-0002-4965-5556"

Knight, Earl E.  ^[1];

• Search DOE PAGES for author "Knight, Earl E."
• Search DOE PAGES for ORCID "0000-0003-0461-0714"

Carmeliet, Jan ^[3]; Johnson, Paul A.  ^[1]

• Search DOE PAGES for author "Johnson, Paul A."
• Search DOE PAGES for ORCID "0000-0002-0927-4003"

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+ Show Author Affiliations

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:

Wed Jun 20 00:00:00 EDT 2018

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE; LANL Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1457309

Report Number(s):

LA-UR-18-20365
Journal ID: ISSN 2169-9313

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Solid Earth

Additional Journal Information:

Journal Volume: 123; Journal Issue: 7; Journal ID: ISSN 2169-9313

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; Stick-slip; Granular material; Fault gouge; FDEM; Earthquake