Does the direct effect of friction increase continuously with absolute temperature?

• 成果类型: Article
• 署名作者: Barbot, Sylvain
• 署名单位: University of Southern California
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12059
• DOI: 10.1073/pnas.2405111121
• 发表日期: 2024-10-15
• 关键词: state-dependent friction; rock friction; shear properties; alpine fault; stick-slip; EVOLUTION; BEHAVIOR; gouge; time; LAW

摘要

Constitutive models of fault friction form the basis of physics-based simulations of seismic activity. A generally accepted framework for the slip-rate and state dependence of friction involves a thermally activated process, whereby the probability of slip along microasperities adheres to an Arrhenius law. This model, which has become widely adopted among experimentalists and theoreticians, predicts a continuous increase of the direct effect with absolute temperature, but is it observed experimentally? Leveraging comprehensive laboratory data across diverse hydrothermal, barometric, and lithological conditions, we demonstrate that, contrary to the classical view, the direct effect for a given deformation mechanism remains largely temperature- independent. Instead, the incremental shifts in the direct effect often coincide with the brittle to semi-brittle transition, across which distinct deformation mechanisms operate. These considerations challenge the validity of the classical model. Realistic constitutive laws for rock failure within the lithosphere must incorporate the contributions of multiple deformation mechanisms within active fault zones. Significance Establishing a constitutive law governing fault friction is a stepping stone for advancing physics-based predictions of the seismic cycle and associated hazards. A commonly accepted explanation for the slip-rate and state dependency of friction is rooted in the thermal activation of slip at microasperities that form the actual area of contact. The model predicts a continuous increase of the parameter regulating the direct influence of velocity on the frictional resistance. However, this perspective conflicts with numerous laboratory observations portraying a different behavior. Specifically, the direct effect parameter is relatively unaffected by temperature up to the brittle to semi-brittle transition. Addressing these disparities and capturing realistic rock behavior within constitutive laws requires considering the contribution of multiple deformation mechanisms.