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Title: On the role of fluids in stick-slip dynamics of saturated granular fault gouge using a coupled computational fluid dynamics-discrete element approach: STICK-SLIP IN SATURATED FAULT GOUGE

The presence of fault gouge has considerable influence on slip properties of tectonic faults and the physics of earthquake rupture. The presence of fluids within faults also plays a significant role in faulting and earthquake processes. In this study, we present 3-D discrete element simulations of dry and fluid-saturated granular fault gouge and analyze the effect of fluids on stick-slip behavior. Fluid flow is modeled using computational fluid dynamics based on the Navier-Stokes equations for an incompressible fluid and modified to take into account the presence of particles. Analysis of a long time train of slip events shows that the (1) drop in shear stress, (2) compaction of granular layer, and (3) the kinetic energy release during slip all increase in magnitude in the presence of an incompressible fluid, compared to dry conditions. We also observe that on average, the recurrence interval between slip events is longer for fluid-saturated granular fault gouge compared to the dry case. This observation is consistent with the occurrence of larger events in the presence of fluid. It is found that the increase in kinetic energy during slip events for saturated conditions can be attributed to the increased fluid flow during slip. Finally, our observationsmore » emphasize the important role that fluid flow and fluid-particle interactions play in tectonic fault zones and show in particular how discrete element method (DEM) models can help understand the hydromechanical processes that dictate fault slip.« less
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [5]
  1. Chair of Building Physics, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich Switzerland; Laboratory for Multiscale Studies in Building Physics, Swiss Federal Laboratories for Materials Science and Technology (Empa), Zurich Switzerland; Department of Civil, Environmental and Geomatic Engineering, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich Switzerland
  2. Solid Earth Geophysics Group, Los Alamos National Laboratory, Los Alamos New Mexico USA; Department of Physics, University of Nevada, Reno, Reno Nevada USA
  3. Solid Earth Geophysics Group, Los Alamos National Laboratory, Los Alamos New Mexico USA
  4. Department of Geosciences, Pennsylvania State University, University Park Pennsylvania USA
  5. Chair of Building Physics, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich Switzerland; Laboratory for Multiscale Studies in Building Physics, Swiss Federal Laboratories for Materials Science and Technology (Empa), Zurich Switzerland
Publication Date:
Report Number(s):
LA-UR-17-23011
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 Volume: 122; Journal Issue: 5; Journal ID: ISSN 2169-9313
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC); ETH Zurich (Switzerland)
Contributing Orgs:
Swiss Federal Lab. for Materials Science and Technology, Zurich (Switzerland); Univ. of Nevada, Reno, NV (United States); Pennsylvania State Univ., University Park, PA (United States)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Earth Sciences
OSTI Identifier:
1356156