1. Describe how earthquakes occur. Compare and contrast the different types of seismic waves. What are seismic waves? 03/02/2015

2. Can earthquakes occur in Chicago?

6. Forces within the Earth Tectonic plates are not smooth along their boundaries. They do not slide easily past one another. Rocks in the plates resist movement, resulting in stress buildup.

7. Earthquake Sudden slip on a fault Results in ground shaking and radiating seismic energy Causes – Volcanic activity – Tectonic plate movement

8. Faults A fracture in the Earth Normal, Reverse, Strike-slip – Strike-slip faults are most destructive Normal ReverseStrike-slip

9. Faults

11. Earthquake Sudden slip on a fault Results in ground shaking and radiating seismic energy Causes – Volcanic activity – Sudden stress changes in the Earth

12. Diagram of an Earthquake Hypocenter/Focus: point underground where the waves originate Epicenter: point on Earth’s surface directly above the focus. Seismic Waves: energy radiating around from the focus in wave form.

13. Seismic Energy 3 types of waves – Primary, Secondary, Surface

14. 1. Primary wave (P-wave)

16. Causes rocks to be squeezed and pushed parallel to the direction of the wave. Fastest wave.

17. 2. Secondary waves (S-waves)

19. 2. Secondary Wave (S-wave) Causes rocks to move perpendicular to the wave direction Slower than P-waves

20. P-waves and S-waves are both BODY waves because they pass through Earth’s interior.

21. 3. Surface Wave Travel only along Earth’s surface Cause the ground to move sideways and up and down Most destructive

22. 3. Surface Wave

26. Seismic Energy