Transition from stick-slip to stable sliding due to asperities aging: experimental evidence on a simulated fault

HR: 0800h
AN: T21B-0471 [Abstracts]
TI: Transition from stick-slip to stable sliding due to asperities aging: experimental evidence on a simulated fault
AU: * Voisin, C
EM: christophe.voisin@ujf-grenoble.fr
AF: LGIT-CNRS, Universit‚ de Grenoble, BP 53, Grenoble, 38041 France
AU: Renard, F
EM: francois.renard@ujf-grenoble.fr
AF: LGIT-CNRS, Universit‚ de Grenoble, BP 53, Grenoble, 38041 France
AU: Grasso, J
EM: jean-robert.grasso@ujf-grenoble.fr
AF: LGIT-CNRS, Universit‚ de Grenoble, BP 53, Grenoble, 38041 France
AU: Stiers, F
EM: frank.stiers@ujf-grenoble.fr
AF: LGIT-CNRS, Universit‚ de Grenoble, BP 53, Grenoble, 38041 France
AB: We have devised a very slow friction experiment (velocity ranging from 0.1 up to 500 æm/s) to investigate the frictional behavior of a block slider. The sample made of salt or PMMA is placed under normal load and a shear displacement is applied at a constant rate. Both forces and horizontal and vertical displacements are recorded in time. The experiment is placed under an optical microscope that allows for a direct observation of the frictional interface. We investigate the dry friction of a salt sample over a flat glass surface. As expected, a transition from stick-slip behavior at low velocities to continuous sliding at large velocities is observed. Focusing on the stick-slip cycle, we document a three stage process. The first part consists of a quasi linear growth of the displacement, followed by an exponential growth. The last stage is formed by a power-law growth of shear displacement. This last stage is not observed so far for PMMA samples and cannot be explained by a regular rate-and-state friction law. The long-term frictional behavior of the salt/glass interface exhibits another transition, from a stick-slip behavior to a stable sliding mode. This transition might be controlled by some aging of asperities on the frictional surface.
DE: 7209 Earthquake dynamics (1242)
DE: 8010 Fractures and faults
DE: 8034 Rheology and friction of fault zones (8163)
SC: Tectonophysics [T]
MN: Fall Meeting 2005