1. Do Now:
What do you know about earthquakes?

2. Turn and Talk: What kind of damage do you expect from an earthquake?
Can it be prevented?

3. Learning Objective:
I will be able to explain what causes earthquakes and where they occur.

4. Success Criteria: I can explain what an earthquake is.
I can explain where earthquakes occur.
I can explain what causes earthquakes through elastic rebound and faults.

5. EARTHQUAKES sudden movement or shaking of the Earth
Caused by plate tectonic stresses
Located at plate boundaries
Resulting in breakage of the Earth’s brittle crust

7. Earthquake Locations Around the World

8. Do we understand how and where earthquakes occur?

9. What do you think causes Earthquakes?

10. Video Clip: While watching the following clip answer the following:
Where do earthquakes occur?
What causes an earthquake?
What is a fault?
What is elastic rebound?

11. PLATE TECTONIC STRESSES
Plate boundaries and faults (= cracks where plate sections are moving in different directions) cause friction as plates move
Plates in a fault zone have STICK-SLIP motion
Periods of no movement (stick) and fast movement (slip)
Energy stored as plates stick,
Energy released as plates slip

12. A. ___________________
Elastic Rebound Theory
Sudden release of progressively stored strain
Tectonic forces act on a rock over a
long period of time
Stored energy exceed the rock’s strength
Rock suddenly breaks, causing an earthquake

13. Scarp caused by the Denali fault earthquake
Faults
The most common source of earthquakes felt by people
Fault motions don’t necessarily break the surface.
Recent California earthquakes are related to buried thrust faults.
Eastern U.S. earthquakes have no surface displacement
Faults cause hazards.
Scarp caused by the Denali fault earthquake
in Alaska, November 3, 2002

14. EARTHQUAKE DAMAGE
Landslides
Building damage
Liquefaction

15. EARTHQUAKE DAMAGE
Most caused by SURFACE waves (arrive last)

16. Do we understand what causes earthquakes?

17. Summary:
Exit Slip