Here's how it works:

1. Stress Build-up: Over time, tectonic plates move and exert pressure on each other. This pressure, called stress, builds up along the fault line.

2. Elastic Deformation: The rocks on either side of the fault are strong, but they can only bend so much. As the stress increases, the rocks deform elastically, like a rubber band being stretched.

3. Rupture and Earthquake: Eventually, the stress exceeds the strength of the rocks. The rocks suddenly fracture, causing a rupture along the fault line. This sudden release of energy causes the ground to shake, which we experience as an earthquake.

4. Elastic Rebound: As the rocks on either side of the fault snap back to their original shape, they release the stored energy. This sudden rebound is what generates the seismic waves that travel through the Earth.

Key Points about Elastic Rebound Theory:

* Fault lines are not smooth: The rough surfaces of the fault line cause the rocks to stick together, building up pressure.

* Stress is released: When the rocks finally break, the stored energy is released as seismic waves.

* Aftershocks: The rocks may continue to adjust after the initial rupture, causing smaller earthquakes called aftershocks.

Elastic rebound theory is a fundamental concept in understanding the cause of earthquakes and how they release energy.