1. Earthquakes

3. Earthquakes
Shaking of the earths crust caused by the release of energy
Causes
Volcanic eruption
Collapse of a cavern
Impact of meteor
Shift of earths plates
Most occur here

4. Anatomy of an Earthquake
Fault
Break in the plate/plate boundary Focus
Point at which rock begins to move
Epicenter
Point on earths surface directly above the focus

5. Why is important for scientists to know where an earthquakes epicenter is located?
Helps predict location of future earthquakes

6. Elastic-Rebound theory
Friction prevents plate movement
Plates deform and change shape
When stress is stronger than friction the plates shift releasing the energy

7. Types of Faults Thrust fault Normal fault Strike-Slip fault
forms as a result of horizontal compression.
Normal fault
forms as a result of horizontal tension
Strike-Slip fault
fractures caused by horizontal shear.

8. Earthquake Waves Energy released from earthquakes travel in waves
3 types of Waves
1. Primary waves (P-waves)
Compress and expand like an accordion
First wave to arrive at the seismograph
Can move through all material

9. 3. Surface waves 2. Secondary waves (S-waves)
Vibrate side to side and up and down
Move only through solid
3. Surface waves
Produce severe ground movements
Move slow and cause most damage

10. The greater the time between the two the farther away the earthquake.
How Do Scientist locate the Epicenter?
Scientist locate the epicenter by measuring the difference between the arrival time of the P and S waves.
The greater the time between the two the farther away the earthquake.