How stress cause movement at faults?

Stress accumulation along geological faults occurs due to tectonic forces exerted on the Earth's crust. When the stress exceeds the frictional resistance of the rocks along a fault, it leads to sudden movement, resulting in an earthquake. This movement can occur in various forms, such as slip or strike-slip, depending on the orientation of the fault and the direction of the applied stress. Ultimately, the release of built-up stress is what triggers the displacement along the fault line.