1. Do Now – In Notebooks  What are some effects of earthquakes?  Why is intensity not always the same as magnitude for an earthquake?

2. EARTHQUAKE HAZARDS How can earthquakes affect society?

3. Structural Failure  Stone and concrete  Easily damaged  Wooden structures  Withstand Earthquakes Better  Steel-framed buildings  High rises are reinforced to make them earthquake resistant

4. Structural Failure  “Pancaking”  Supporting walls of a building fail and an intact level above falls

5. Aftershocks  A ground tremor caused by the repositioning of rocks after an earthquake

6. Land and Soil Failure  Massive landslides  Earthquakes liquefy surface materials which then behave like quicksand  Greatest damage in soft soil

7. Earthquake Evidence  Fault scarps  Areas of great vertical offset

8. Tsunami  A tsunami is a series of water waves generated by a disturbance in the ocean.

9. How do Tsunamis form?  Tsunami sources displace water in the ocean  Gravity then acts to restore displaced water  A wave is generated that travels as an expanding ring across the ocean’s surface

11. Earthquake Forecasting  Calculating the probability of an earthquake  Done by following:  History of Earthquakes in an area  Rate at which strain builds up in the rocks

12. Where do Earthquakes Occur?  Earthquakes are not randomly distributed  Majority of earthquakes occur along seismic belts (Almost 80% at Circum-Pacific Belt)  Seismic gaps  Place along an active fault that has not experienced an earthquake for a long time