9627895 Marone The PIs propose to study the frictional properties of simulated faults under the temperatures, pressures, and fluid conditions that exist within the nucleation region of large earthquakes. This experimental program will focus on the rate at which faults strengthen with time, the physical and chemical processes that cause fault healing and lithification in fault gouge, and the rate/state friction constitutive properties under hydrothermal conditions. The experiments will be conducted at pressures, temperatures and fluid conditions simulating the upper 10 to 15 km of the earth's crust. ***
