Time-dependent friction in rocks
Abstract
Friction experiments have been conducted on porous sandstone, quartzite, graywacke, and granite in the 20- to 850-bar normal stress range. Sliding on clean rough-ground surfaces is initially stable for this range. However, as powered rock debris accumulates on the slip surface, stick slip becomes the dominant mode of sliding. The coefficient of static friction of surfaces with gouge exhibits a highly time-dependent behavior. Static friction increases with the logarithm of the time that adjacent blocks remain in stationary contact. Over the entire range of normal stresses the static friction for 105-sec intervals between stick-slip events is greater than the static friction for 15-sec intervals by 6 to 10%. This behavior may be significant in understanding the mechanisms of earthquake foreshocks, aftershocks, and fault creep.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- July 1972
- DOI:
- 10.1029/JB077i020p03690
- Bibcode:
- 1972JGR....77.3690D
- Keywords:
-
- Deformation;
- Engineering Geology;
- Igneous Rocks;
- Sedimentary Rocks;
- Mineralogy;
- Petrology;
- and Physical Properties of Rocks: Elasticity;
- fracture;
- and flow;
- Seismology: General or miscellaneous