Coupled thermo-hydro-mechanical processes in fault zones during rapid slip

The physical processes which occur during an earthquake exhibit several coupled phenomena as large variations of stress, pore pressure and temperature take place in the slip zone. Thermo-poro-mechanical couplings due to shear heating can be associated to phase transition such as vaporization of the pore fluid, melting of fault gouge and to chemical effects such as dehydration of minerals or decarbonation of calcite. Different competing effects may influence dynamic slip and affect the weakening of the shear stress. In this paper, we show how thermal pressurization of the pore fluid and thermal decomposition of minerals induced by shear heating limit the co-seismic temperature rise which may explain the lack of pronounced heat outflow, and the lack of shallow frictional melting, along major tectonic faults. ha l-0 05 62 45 7, v er si on 1 3 Fe b 20 11 Author manuscript, published in "Rock Mechanics in Civil and Environmental Engineering, EUROCK 2010, Lausanne : Switzerland (2010)"