Stability Analysis of Creeping Faults: The Role of Chemical Decomposition of Minerals

The stability of creeping faults is studied under the effect of shear heating, pore fluid pressurization and mineral decomposition. Such reactions enhance the pore fluid pressurization because they release fluid, but they limit the temperature rise because they are endothermic. The stability of stationary slip is investigated by performing a linear perturbation analysis. It is shown that chemical reactions change a stable behaviour into an unstable one when the pore pressure effect is larger than the endothermic effect. It is shown that the opposite effect can also be observed when the dehydration reactions can trigger an arrest of the fault. Mineral decomposition can thus strongly modify the nucleation of seismic slip.