No abstract

Fault zones play a key role in fluid, heat, and solute transport, and thereby affect many important hydrogeological processes (Bense et al., 2013;Manga et al., 2012). Previous studies have shown that fault zones act as hydraulic conducts, barriers, or mixed conduit/barrier systems, depending on their structure, petrophysical properties, and 3D geometry (Caine et al., 1996). Yet, such properties are not easily measured in situ as many are located in low-permeability fractured crystalline rock (Xue et al., 2016). Conventionally, hydrogeologists employ field tests (e.g., aquifer pumping tests, slug tests) to estimate hydrogeological properties. Alternatively, structural geologists use discrete fracture network (DFN) modeling (Giuffrida et al., 2019;Panza et al., 2016) or mini air-permeameters to characterize the permeability (Bense et al., 2013). Note that conventional hydrogeological methods examine intergration at larger scales (>10 m), while structural methods focus on microstructure (<1 m), often resulting in a gap between local and regional scales that makes it difficult to uniquely characterize the fault-damage zone.Additionally, these methods are costly and do not provide hydrodynamic information on the temporal evolution of the hydrogeological properties of the fault zone. Previous studies have shown that the hydrogeological properties