The intense seismic activity in Oklahoma during the 2010-2020 period was attributed to reactivation of basement faults due to wastewater injection. Our mapping of basement faults in the subsurface (e.g., Kolawole et al., 2019) provided limited resolution of the faults’ structures. Here, we analyze the internal structure of a strike-slip fault in the exposed granitic basement of southern Oklahoma, located at the margins of the seismic activity. The fault, named Off-Road Fault Zone (ORFZ), displays a ~260 m-wide zone that is dominated by multiple fracture systems which were analyzed by utilizing satellite, high-resolution drone images, field observations, and a 2-D shallow electrical resistivity imaging. The ORFZ hosts sub-vertical NE-striking fracture clusters with predominantly tensile fractography, en-echelon segmentation, few horizontally striated slickensided surfaces, hematite-veins, epidote veins, and distributed gouge-lenses. Scan-line fracture mapping revealed three fracture intensity zones: Core-clusters with intensity of >10 fractures/m, damage zones with intensities of 0.1– 10 fractures/m, and, country rocks with background lower intensity. The gouge lenses and slickensided fractures are restricted to the core zone indicating increasing shear deformation concurrent with increasing fracture saturation. The mapped deformation, which is a wide zone dominated by tensile fractures and minor shear, is interpreted as the early evolution of a major strike-slip fault in homogenous crystalline basement. The width of the analyzed fault zone (~260 m) suggests that it may extend to depth of a few km and could be associated with the few local seismic events.