Seismo Lab Brown Bag Seminar

The slip instability and dynamic rupture that leads to earthquakes is regarded as a frictional phenomenon, and an important problem is characterizing the frictional weakening of faults at earthquake slip rates. Dynamic weakening by flash heating occurs at highly-stressed asperity contacts as slip rates approach seismic rates, and the magnitude of weakening increases with surface temperature. In this talk, I will present results from rock friction experiments using a high-speed biaxial apparatus equipped with a high-speed infrared camera to explore the role of surface temperature on flash heating. We combined 1-D thermal models with measured surface temperature to constrain the evolution of normal stress and flash temperature at the mm-scale, and incorporated this evolution into a flash-weakening model. Model predictions are improved when inhomogeneous normal stress is considered in combination with micron and mm sized asperity contacts.