1. Faults & Stress Write everything in BLUE!
Earthquakes
Faults & Stress
Write everything in BLUE!

2. What are Earthquakes?
The shaking or trembling caused by the sudden release of energy beneath Earth’s surface.
Usually associated with faulting or breaking of rocks
Continuing adjustment of position results in what is known as aftershocks

3. What is stress? The force that acts on rock to change its shape
3 Types of stress
Shearing
Tension
Compression

4. Shearing: stress that pushes rock in opposite directions
Shearing: stress that pushes rock in opposite directions. Causes masses of rock to slip past each other.

5. Tension Stress that stretches rock so it becomes thin in the middle.
Causes valleys

6. Compression Stress that squeezes rock until it folds or breaks.
Causes hills

7. Questions
What is the relationship between compression and a convergent boundary?

8. Questions
What is the relationship between compression and a convergent boundary?
Both compression and convergent boundary squeezes rocks together to form mountains or hills.

9. How is energy stored in Rocks?
Rocks are put under stress so they become deformed or bend.
Once 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

10. A break in the Earth’s crust is called a Fault
3 types of faults

11. Strike-Slip Fault There is little up or down motion
A strike-slip fault that forms the boundary between two plates is called a transform boundary.
Shearing stress causes strike-slip faults

12. Strike-Slip Fault Example

14. Normal Fault The hanging wall slips downward below the footwall.
The Normal Fault that forms the boundary between two plates is called a divergent boundary.

15. Normal Fault Example: Rio Grande Rift Valley

16. Reverse Fault The hanging wall slides up and over the footwall.
The reverse fault that forms the boundary between two plates is called a convergent boundary.

17. Reverse Fault Example: Appalachian Mountains (East Coast)

18. Questions
Explain the difference between a normal and reverse fault

19. Questions Explain the difference between a normal and reverse fault
A reverse fault is formed at a convergent boundary and creates mountains. A normal fault is formed with divergent boundaries and forms valleys

20. Worst Earthquakes in the US
New Madrid fault on the Mississippi River in 1811
8.1 Magnitude
Epicenter in northern Arkansas
35% chance of another major earthquake in the next 50 years

21. New Madrid, MO