1. Chapter 8 Section 1 Earthquakes: Vibration of Earth created when there is a rapid release of energy Caused by slippage along a fault Faults are fractures in Earth where movement has occurred

2. Tension forces Compression forces Shearing forces

3. Focus – point where an earthquake begins Epicenter – point on the surface above the focus Seismic waves – any energy waves made by an earthquake

4. 1300 Km long Displacement can occur 100-200 km at a time Some sections move slowly Some sections lock for hundreds of years and then break

5. Views of the San Andreas Fault

6. The Cause of Earthquakes: Rapid release of energy Forces in the Earth deform rock – stores elastic energy - suddenly breaks Energy released as seismic waves Elastic rebound – the tendency for a rock to spring back after an earthquake Aftershocks – earthquake that occurs soon after a major earthquake Foreshock – small earthquakes occurring before a major earthquake