S1, S4: Earth materials science related to igneous processes and plate convergence region (Joint Special Session)

[S1,S4-03] Temperature dependence of direct effect on the friction of single-crystal muscovite from room to elevated temperature

*Hiroshi Sakuma¹, Diane Moore², David Lockner² (1. NIMS, 2. USGS)

Keywords:Direct effect, Thermal activation process, Mica, Molecular dynamics, Rate and state friction law

We have studied the direct-effect parameter “a” which is the critical parameter in the rate and state friction law for the response of the change in slip rate. Our velocity-stepping shear tests on single-crystal muscovite indicate that the “a” value clearly decreases with increasing temperature. The simulated “a” value by molecular dynamics method decreases with increasing temperature at high shear rate. At shear rates <10¹⁰ s⁻¹, the values are constant independent of temperature. These results may not be interpreted by the thermal activation theory.