1. Earth Science Notes
Earthquakes

2. Objectives I can… Identify fault types
Normal, reverse, strike-slip
Explain how an Earthquake occurs
Elastic limit / Elastic Rebound / Plate Tectonics
Describe the types of waves generated by and earthquake
P-waves / S-waves / Surface-waves

3. How Faults Form Rocks can bend, compress or stretch
When rocks can no longer do this they break – creating a fault

4. Fault Types
Normal Faults – form when rocks are diverging

5. Normal Faults

6. Fault Types
Reverse Faults – form when rocks are converging

7. Reverse Faults

8. Fault Types Strike-Slip Faults –form when rock moves past another rock
Displacement is such that the material on the other side of the fault appears to be displaced to the left.
Displacement is such that the material on the other side of the fault appears to be displaced to the right.

9. Strike-Slip Faults

12. What is an Earthquakes?
When plates move along faults it puts stress on rocks at the plates edge
Vibrations caused by plate movements are called earthquakes.

13. How Earthquakes Occur Rocks move along faults and catch on each other.
Forces continue to build on rocks and they begin to distort.
Once the rocks reach their elastic limit they break.
Elastic rebound
Rocks readjust themselves and return to their original shape.

14. How Earthquakes Occur

15. Elastic Rebound

16. Elastic Limit is reached

17. Earthquakes Create Waves
Seismic Waves – waves that move through the earth that were created by an earthquake
Measured by a Seismograph
measures wave magnitude and time
There are horizontal and vertical LINES

18. Types of Seismic Waves
Primary Waves (P-Waves) – causes rocks to move back and forth in a linear manor

19. P - Waves

20. Types of Seismic Waves
Secondary Waves (S-Waves) – causes rocks to move at right angles in relation to the direction of the wave

21. S- Wave

22. S- Waves S-waves do not travel through fluids.
Do not exist in Earth’s outer core. (inferred to be primarily liquid iron).
S waves travel slower than P waves in a solid and, therefore, arrive after the P wave.

23. P v. S Wave

24. Types of Seismic Waves
Surface Waves – causes rock to move in a backwards rolling motion
Most destructive type
Produced when earthquake energy reaches the surface
Epicenter – point on the earth’s surface directly above the focus

25. Surface Waves

26. Wave Comparison

27. Summary Be able to… Identify fault types
Normal, reverse, strike-slip
Explain how an Earthquake occurs
Elastic limit / Elastic Rebound / Plate Tectonics
Describe the types of waves generated by and earthquake
P-waves / S-waves / Surface-waves