Relationship between textures and sliding motion of experimentally deformed fault gouge: Application to fault zone behavior

The run products of many triaxial friction experiments on clay-rich and quartzofeldspathic gouges have been examined petro- graphically, to see if any physical differences between stable and stick-slip motion can be found that will help to identify the cause of earthquakes and/or be useful for paleoseismology. For both gouge types the transition from stable sliding to stick-slip is correlated with (1) a change from pervasive deformation of the gouge layer to localized slip in subsidiary shears, and (2) an increase in the angle between the crosscutting (Riedel) and boundary-parallel shears. A possible hypothesis to explain earthquakes based on these differences is that the localization of slip creates the…