Effects of loading rate and normal stress on stress drop and stick-slip recurrence interval

摘要: In this paper we report on investigations of frictional restrengthening during repetitive stick-slip initially bare granite surfaces (nominal contact area 25 cm 2 ). The tests were conducted in a double-direct shear apparatus at room-temperature and humidity. Normal stress was held constant, induced by controlling the velocity loading piston. Samples exhibited quasi-periodic instabilities. Appreciable yielding precursory creep occur prior to failure. Stress drop amplitudes range from 0.1 3.1 MPa (or 4-49% failure strength). We study effects rate (0.5 300 μm/s) normal load (5 10 MPa) recurrence interval. At given rate, there is positive correlation between interval, indicating healing rates ∼4 per decade increase time. However, combined data all velocities show lower suggesting an apparent ∼1 find consistent scaling different when compared inter-event displacement. for delineate single trend larger drops greater pre-failure Failure strength post-slip levels converge with increasing velocity. Our indicate that post-seismic depend interval complex way.