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Dynamic friction in sheared fault gouge: Implications of acoustic vibration on triggering and slow slip

Jean M. Carlson, Ahmed E. Elbanna, & Charles K. Lieou

Published March 11, 2016, SCEC Contribution #7884

Abstract Friction and deformation in granular fault gouge are among various dynamic interactions
associated with seismic phenomena that have important implications for slip mechanisms on earthquake
faults. To this end, we propose a mechanistic model of granular fault gouge subject to acoustic vibrations
and shear deformation. The grain-scale dynamics is described by the Shear-Transformation-Zone theory of
granular flow, which accounts for irreversible plastic deformation in terms of flow defects whose density is
governed by an effective temperature. Our model accounts for stick-slip instabilities observed at seismic slip
rates. In addition, as the vibration intensity increases, we observe an increase in the temporal advancement
of large slip events, followed by a plateau and gradual decrease. Furthermore, slip becomes progressively
slower upon increasing the vibration intensity. The results shed important light on the physical mechanisms
of earthquake triggering and slow slip and provide essential elements for the multiscale modeling of
earthquake ruptures. In particular, the results suggest that slow slip may be triggered by tremors.

Carlson, J. M., Elbanna, A. E., & Lieou, C. K. (2016). Dynamic friction in sheared fault gouge: Implications of acoustic vibration on triggering and slow slip. Journal of Geophysical Research: Solid Earth, 121(3), 1483-1496. doi: 10.1002/2015JB012741. http://onlinelibrary.wiley.com/doi/10.1002/2015JB012741/full

Related Projects & Working Groups
Dynamic friction in sheared fault gouge: implications of acoustic vibration on triggering and slow slip, Fault and Rupture Mechanics (FARM)