Fault geology is a sub-discipline of structural geology and tectonics that investigates the formation, geometry, kinematics, and mechanics of faults and fault systems within the Earth's crust. This field examines how brittle deformation processes accommodate strain, focusing on fault nucleation, propagation, displacement accumulation, and their resultant impact on rock structures and regional tectonic evolution, which is critical for understanding seismic hazards, crustal architecture, and the localization of economic resources.