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A micromechanical model of rate and state friction: 1. Static and dynamic sliding
Author(s) -
Perfettini Hugo,
Molinari Alain
Publication year - 2017
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb013302
Subject(s) - viscoplasticity , scaling , slip (aerodynamics) , state variable , mechanics , plasticity , materials science , shear (geology) , statistical physics , classical mechanics , physics , geometry , mathematics , composite material , constitutive equation , thermodynamics , finite element method
Rate and state friction has been extensively used to explain many features of the seismic cycle but the scaling of the experimentally derived parameters a , b and d c for real faults is problematic. The purpose of this paper is to present a micromechanical model for rate and state friction in which the contact between the two surfaces occur via plastic and elastic contacts. Shear deformation is accommodated in the bulk of cylindrical contacts rather than at the surface of the contact, as done classically. Assuming that the viscoplastic response is governed by the J 2 plastic flow theory, we retrieve the rate and state framework. Unlike previous works, we identify the state variable as representing the changes of plastic contact area. In our model, all macroscopic frictional parameters of the rate and state framework are related to the parameters of the elementary contacts. We provide a derivation of the aging evolution law for the state variable and propose a new evolution law that reconciles the aging, Linker‐Dieterich and Nagata evolution laws. We discuss the scaling of the frictional parameters for active faults and landslides. The a and b parameters should have comparable value at fault scale since friction is mostly controlled by plastic contacts at large normal stress (typically hundreds of MPa). Our model predicts that the critical slip distance d c should be scale independent and controlled solely by the plastic contacts.