Fluid-induced fault reactivation: micromechanics and seismic risk management

Earthquake activity resulting from fluid injection into underground rock formations threatens our sustainable utilisation of the subsurface. Injected fluids change the tectonic stress distribution, potentially reactivating pre-existing weak slip surfaces, or faults. Understanding fault behaviour under these changing stress conditions is key to seismic risk management. The proposed experiment involves deforming a rock to generate a ‘natural’ shear fault and then inducing fault slip by fluid injection. Operando tomographic imaging will, for the first time, allow observation of fluid-induced grain-scale micromechanical rupture processes, quantification of the volumetric strain in the fault normal direction, and concurrent observation and quantification of the competition between fault rupture and fluid pressure fronts during injection-induced reactivation. This proposal is supported through the EXCITE network (https://excite-network.eu), EXCITE2 TNA Call 2 reference E2-C2-73.