Dilatancy stabilises shear failure in rock

Failure and fault slip in crystalline rocks is associated with dilation. When pore fluids are present drainage insufficient, dilation leads to pressure drops, which turn lead strengthening of the material. We conducted laboratory rock fracture experiments direct in-situ fluid measurements demonstrate that dynamic rupture propagation can be stabilised (i.e., become quasi-static) by such a dilatancy effect. also observe that, for same effective pressures but lower pressures, stabilisation process may arrested when approaches zero vaporises, resulting shear failure. In case stable rupture, we witness continued prolonged after main failure event result recharge zone. All our observations quantitatively explained spring-slider model combining slip-weakening behaviour, slip-induced dilation, diffusion. Using data an inverse problem, estimate key parameters controlling stabilisation, rate zone storage. These estimates used make predictions drop faulting, where crust expect or vaporisation during earthquakes. For intact well consolidated faults, strong between 4 6 km depth regardless ambient pressure, at greater depths lithostatic pressure. uppermost part (<4 km), predict limits strengthening. The dilatant most likely coincide geothermal energy reservoirs (typically 2 5 depth) regions slow events observed (pore pressure).