1. Earthquakes Liz LaRosa http://www.middleschoolscience.com 2009http://www.middleschoolscience.com

2. What is an earthquake? TB pg. 211 Vibrations in the ground that result from movement along breaks in the earth’s lithosphere. Can also be caused by volcanic or magmatic activity

3. Three Types of Faults, TB pg.213 Strike-Slip - Occurs on a transform boundary Reverse- Occurs on a convergent boundary Normal- Occurs on a divergent boundary

4. What causes earthquakes? TB pg. 213 Tectonic plates move past each other causing stress. Stress causes the rock to deform – Plastic deformation – does not cause earthquakes – Elastic deformation – rock stretches then reaches a breaking point, releasing energy.

5. Elastic Rebound – deformed rock goes back to its original shape http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

6. TB pg. 214 Focus – point inside the Earth where an earthquake begins Epicenter – point on Earth’s surface above focus

7. How Seismographs or Seismometers Work, TB pg. 217 http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM the pendulum remains Video link: http://www.cleanvideosearch.com/media/action/yt/watch?v=Gbd1F cuLJLQground moves beneath it -measures ground motion and can be used to determine the distance seismic waves travel

8. Typical Seismogram- a graphical illustration of EQ waves http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

9. Primary Waves (P Waves) TB pg. 215 A type of seismic wave that compresses and expands the ground The first wave to arrive at an earthquake http://daphne.meccahosting.com/~a0000e89/insideearth2.htm

10. Secondary Waves (S Waves) TB pg. 215 A type of seismic wave that moves the ground up and down or side to side http://daphne.meccahosting.com/~a0000e89/insideearth2.htm

11. Comparing Seismic Waves

12. Surface Waves, TB pg. 215 Move along the Earth’s surface Produces motion in the upper crust – Motion can be up and down or rolling motion – Travel more slowly than S and P waves More destructive

13. How do scientists calculate how far a location is from the epicenter of an earthquake? Scientists calculate the difference between arrival times of the P waves and S waves-use 3 seismic stations Triangulation locates the earthquakes epicenter

14. Locating Earthquakes http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

15. Locating Earthquakes http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

16. Locating Earthquakes http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

17. How are Earthquakes Measured? 3 Scales are used:  Richter Scale-magnitude-from 0-no limit, amount of ground motion  Moment magnitude-magnitude— total amount of energy in EQ  Modified Mercalli Scale-intensity- measures damage from shaking, I- XII

18. Richter Scale

19. How are Earthquakes Measured? Mercalli Intensity Scale Click Link for Interactive Demo http://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swf http://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swf

20. San Francisco Earthquake, 1989 History Channel Video http://www.history.com/topics/1989-san-francisco-earthquake http://www.civildefence.govt.nz/assets/Uploads/images/rail- damage.jpg

21. Earthquake Waves & Earth’s Interior

22. Earthquake Risk-TB pg. 220

23. Tsunamis Brain POP-click on pic http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

24. Formation of a tsunami http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

25. Tsunami Warning System http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt