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.

中文翻译：

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热液条件下的岩石摩擦实验和建模


沿构造断层的摩擦不稳定性会产生一系列滑动行为，包括抗震蠕变、慢震和常规地震。热控制岩石摩擦为岩石断层的摩擦特性以及随着地壳深度增加而相关的地震行为提供了新的见解。我们首先回顾标准费率和州摩擦法。然后我们重点讨论单一、混合和天然凿岩的水热摩擦实验。稳态摩擦和速度依赖性随着温度的升高而显着变化。随着温度升高，岩凿的稳态摩擦系数可能逐渐增大、大致恒定或波动。在高温下，一些凿孔可能会出现脆性-延性转变。此外，随着温度的升高，岩石摩擦力在速度增强和速度减弱之间切换。这种变化表明了断层稳定性转变的热约束，并为地震活动的温度和深度分布提供了可能的解释。我们研究了热液条件下的四种摩擦模型：经典的速率、状态和温度相关摩擦模型、流动摩擦模型、幂律速率、状态和温度相关摩擦以及扩展的微观物理（ Chen-Niemeijer-Spiers）模型。水热摩擦实验和基于物理的模型可以增强我们对断层摩擦的理解。需要进一步研究孔隙流体的影响、多重变形和愈合机制、高温下的微观结构演化，以及实验数据和摩擦模型对自然地震和诱发地震的外推。