Integrated characterization of an active fault, insights from fault geometry, roughness and properties

Fault planes are geometrically rough and non-planar due to their frictional properties. The impact of active faults on the host rock properties is a dynamic process that affects the fluid flow around the fault and hence the mineralogy of both the host rock and the fault rocks. These would influence the stiffness of fault rocks, the size of potential earthquakes and the location of rupture nucleation. In this study, we have investigated a well-exposed active fault plane in Granada Basin, through photogrammetry of outcrops (drone imagery), structural measurements and frequency distribution of fault and fractures as well as non-destructive measurements of permeability and Young’s modulus. Furthermore, we have estimated roughness on the images of the main fault plane by a novel approach utilizing Root Mean Square intensity distribution. This is the first integrated study that relates the distribution of faults and fractures to the fault rock properties and roughness on an active fault. Young’s moduli values are higher, while permeability values are lower, where the fault rocks are exposed corresponding to the locations of minor faults cutting through the main fault plane. These locations show higher roughness on the images of the fault plane. The observed fault rocks of the fault core encompass enhanced granulation and wearing process during the fault slip. This integration of different data contributes to a better understanding of active faults and their properties, which eventually be important for the knowledge of fault seismicity in the future. • Fault roughness was estimated on the drone images of an active fault plane by a novel approach utilizing Root Mean Square intensity distribution. • Young’s moduli values are higher, while permeability values are lower, where the fault rocks are exposed corresponding to the locations of minor faults cutting through the main fault plane. • There is higher roughness on the fault plane where minor faults and fault rocks are present.