Relating high-velocity rock-friction experiments to coseismic slip in the presence of melts

摘要: The dynamic strength (τ f ) of faults during coseismic slip is a major unknown in earthquake mechanics, though it has crucial influence on rupture properties, stress drop, radiated energy and heat produced slip. In order to provide constraints τ , High-Velocity Rock Friction Experiments (HVRFE) are conducted natural rocks with rotary shear apparatuses, reproducing (several meters) rate (0.1-3 m s -1 typical large earthquakes. Among the various weakening mechanisms possibly activated seismic slip, we focus melt lubrication. Solidified, friction-induced melts (pseudotachylytes) decorate some exhumed faults, showing that can occur its frequency still matter debate. presence melt, undergoes an initial strengthening stage, followed by dramatic stage (thermal runaway). Field estimates based pseudotachylyte thickness experimental measures suggest drops once thermal runaway achieved. These compatible high radiation efficiency, as observed for Moreover, threshold onset might explain differences between mechanics small (M < 4) A simple mathematical model coupling melting, extrusion diffusion reproduces features such duration convergence steady-state.