Abstract
Frictional instabilities along tectonic faults produce a full spectrum of slip behaviors including aseismic creep, slow earthquakes, and regular earthquakes. Thermally controlled rock friction provides new insights into the frictional properties of rock faults and associated seismic behaviors with increasing crustal depth. We first review the standard rate and state friction laws. Then we focus on discussing hydrothermal friction experiments on single, mixed, and natural gouges. Steady-state friction and velocity dependence vary significantly with increasing temperature. As temperature increases, steady-state friction coefficients of rock gouges may increase progressively, keep roughly constant, or fluctuate. At high temperatures some gouges may show a brittle-ductile transition. In addition, with increasing temperature, the rock friction switches between velocity-strengthening and velocity-weakening. This variation indicates thermal constraints on the fault stability transition and provides a possible explanation for the temperature and depth distribution of seismic activity. We examine four friction models for hydrothermal conditions: the classical rate-, state-, and temperature-dependent friction model, the friction to flow model, the power-law rate-, state- and temperature-dependent friction, and the extended microphysical (Chen-Niemeijer-Spiers) model. The hydrothermal friction experiments and physically-based models can enhance our understanding of fault friction. Further research is needed on the effects of pore fluids, multiple deformation and healing mechanisms, microstructural evolution at elevated temperatures, and extrapolation of experimental data and friction models to natural and induced earthquakes.
Original language | English (US) |
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Article number | 104824 |
Journal | Earth-Science Reviews |
Volume | 254 |
DOIs | |
State | Published - Jul 2024 |
Funding
We are grateful to the Editor Gillian Foulger, the reviewer Andr\u00E9 Niemeijer, and an anonymous reviewer for their constructive comments. In addition, we would like to express our gratitude to Sylvain Barbot for some discussions that help us better understand his friction model. Partial funding for this study has been provided by the U.S. Department of Energy EERE Geothermal Technologies Office to Utah FORGE and the University of Utah under Project DE-EE0007080 Enhanced Geothermal System Concept Testing and Development at the Milford City, Utah Frontier Observatory for Research in Geothermal Energy (Utah FORGE) site.
Keywords
- Hydrothermal conditions
- Rock friction
- Seismogenic zone
- Steady-state friction
- Temperature dependence
- Velocity dependence
ASJC Scopus subject areas
- General Earth and Planetary Sciences