[DLS] Dan Faulkner (University of Liverpool)

Natural faults display a remarkable variety of slip from fault creep to supershear earthquakes. A physical understanding of fault slip and its variability requires modelling over a range of time and spatial scales. This needs to be underpinned by a fundamental understanding of the operative processes quantified by constitutive relations. Laboratory constraints of fault friction cover only a small part of the parameter range that exists in nature. Recent work involving experiments under hydrothermal conditions and very slow slip rates are reported for fault gouges that represent mature fault zones. The results indicate a trend towards unstable slip at elevated temperature, high pore fluid pressures, and slow slip rates. In order to link laboratory results back to nature, the relations between fault frictional parameters and seismic b-values, geodetically derived friction, and seismic quiescence on major faults are explored.