Exciting news! We're transitioning to the Statewide California Earthquake Center. Our new website is under construction, but we'll continue using this website for SCEC business in the meantime. We're also archiving the Southern Center site to preserve its rich history. A new and improved platform is coming soon!

Velocity- and temperature-dependence of steady-state friction on the Central San Andreas Fault controlled by competing healing mechanisms

Shiying Nie, & Sylvain D. Barbot

Submitted September 11, 2022, SCEC Contribution #12333, 2022 SCEC Annual Meeting Poster #151

The empirical rate- and state-dependent friction law is widely used to explain the frictional resistance of rocks within a narrow range of temperature and sliding velocity. However, the constitutive parameters are often found to vary with temperature and sliding velocity, indicating the potential implication of multiple micro-physical processes acting at different time scales. Here, we explain the mechanical data from natural samples collected on the San Andreas Fault Observatory at Depth (Moore et al. 2016) by invoking the competition between two healing mechanisms with different thermodynamic properties. We present a physical model of rate-, state-, and temperature-dependent friction where the fault strength is modulated by the real area of contact. The flattening of contact junctions is accommodated by various micro-physical processes, such as pressure-solution creep or viscoelastic collapse, that operate at different time scales based on mineralogy and temperature. Considering the competition of two mechanisms with different activation energies, we explain the effect of velocity and temperature on the steady-state friction of the southwest deforming zone (SDZ) with constant constitutive parameters. The transition from velocity strengthening to velocity weakening can be attained either by decreasing the slip velocity or by increasing temperature. Our study provides a framework to understand the physics underlying the empirical rate- and state-dependent friction law and the corresponding laboratory observations. Reproducing the complex frictional properties of the SDZ is key to explaining the evolution of slow-slip events and micro-earthquakes along the creeping segment of the San Andreas Fault.

Citation
Nie, S., & Barbot, S. D. (2022, 09). Velocity- and temperature-dependence of steady-state friction on the Central San Andreas Fault controlled by competing healing mechanisms. Poster Presentation at 2022 SCEC Annual Meeting.


Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)