Stick-slip behavior in saturated fault gouge; insights from grain-scale models Academic Article uri icon

abstract

  • Many natural faults are filled with gouge, an unconsolidated collection of granular material, saturated with fluid. The interactions between fluid pressure and fault stability may exert an important control on fault-stability. Fluids may inhibit or retard earthquakes, due to dilatancy hardening-an increase in the effective stress on grain contacts caused by a drop in pore pressure resulting from porosity increase that accompanies shear. Also, externally-imposed variations in fluid pressure (either natural or man-made) may trigger earthquakes. To explore this dynamic system, we use a grain-scale model based on the discrete element method, coupled with a continuum model of fluid pressure that assumes pressure-driven flow through a permeable material (Goren et al., JGR, 2011). This model allows us to explore the feedbacks between porosity changes arising from rearrangement of grains …

publication date

  • December 1, 2012