What is the sudden return of elastically deformed rock to an undeformed shape?

The sudden return of elastically deformed rock to its undeformed shape is known as elastic rebound. This phenomenon typically occurs during an earthquake when accumulated stress along geological faults exceeds the strength of the rocks, causing them to fracture. As the stored elastic energy is released, the rocks snap back to their original configuration, resulting in ground shaking. This process is a key mechanism behind the release of energy in tectonic plate movements.