A physical understanding of the dynamics of stick-slip instability as an analogue of earthquake rupture is of fundamental importance to earthquake mechanics. To this end, laboratory studies on rock friction can provide crucial data on the friction constitutive relation and the instability behavior. Recent researches have focussed on the determination of parameters for a class of rate and state dependent friction law in the stable sliding stage. Nonlinear stability analysis and computer simulation reveal a wide range of oscillational and dynamic instability behavior, some of which have never been observed and some of which have not been systematically studied in the laboratory. The PI will investigate the velocity dependence of such behavior using a triaxial system with an internal transducer assembly at high normal stress as a test of the theory. Selected tests at elevated temperatures are also planned.
