A geological fault is a fracture or zone of fractures in the Earth's crust along which movement has occurred. These structures represent discontinuities in the rock mass, and the displacement along the fault plane is typically the result of accumulated stress exceeding the rock's strength. Faults are classified based on the relative movement of the rock blocks—for example, normal faults occur due to tensional stress, strike-slip faults involve horizontal shearing motion, and reverse faults result from compressional stress. The study of these faults is crucial for understanding the planet's tectonic processes, as they are primary sites of seismic activity and are associated with various geological hazards, including earthquakes.