Microphysical Modeling of Fault Slip and Stability Transition in Hydrothermal Conditions

Field and laboratory observations indicate that the frictional behaviors of faults depend on hydrothermal conditions. We extend microphysical Chen-Niemeijer-Spiers (CNS) model to conditions by using observed temperature variation indentation hardness infer dependence a parameter . This is assumed constant in previous versions CNS model. A simple spring-slider system used simulate fault investigate steady-state wet granite gouges. Our numerical results quantitatively reproduce experimental data showing frictional-plastic transition. The also describe transition from velocity-strengthening at low temperatures (<160°C), velocity-weakening intermediate (160°C–370°C), then back high (>370°C). In our extended model, these suggest dominant shear deformation mechanism does granular flow fully plastic creep with increasing temperature.