1. Earthquakes

5. Sumatra December 26,

6. Before

7. After

8. Haiti January 12,
230,000 dead 300,000 injured 1,000,000 homeless

9. Chile February 27,

10. China April 14,

11. Where he lived was above the epicenter of a massive quake.
8.9 magnitude
70,000 dead
Pulled his classmates from the building.

12. Japan March 11,

13. http://www.bbc.co.uk/news/world-asia-pacific- 12716204
quake-2011/

14. Earthquakes

15. What are Earthquakes?
Earthquakes are the Earth's natural means of releasing stress.

16. What are Earthquakes?
As the plates move they put forces on themselves and each other.
When the force is large enough, the crust is forced to break.

17. What are Earthquakes
When the break occurs, the stress is released as energy which moves through the Earth in the form of waves, which we feel and call an earthquake.

18. What causes the stress?
When two plates interact at their boundaries they put forces on each other.
There are three main forces that drive deformation within the Earth and create the stress that causes earthquakes.
Compressional Stress
Tensional Stress
Shear Stress

20. Which of the following things are elastic?
Pasta
Rubber bands
Rocks

21. Elasticity
Elasticity is when you change the shape of something and when you release the stress, it goes back to its original shape.
Rocks have elastic properties

22. Elasticity
When forces are applied to rocks, such as pulling, pushing, twisting, or compression, they change their shape.
Once the rock reaches its elastic limit, it breaks and returns to an undeformed shape.
We can use the elastic properties of rock to explain how energy is stored and released within the Earth’s crust.

23. Elastic Rebound Explains how energy is stored in rocks
Rocks bend until the strength of the rock is exceeded
Rupture occurs and the rocks quickly rebound to an undeformed shape
Energy is released in waves that radiate outward from the fault