1. Earthquakes Liz LaRosa http://www.middleschoolscience.com 2009http://www.middleschoolscience.com for my 5 th grade science class 2009

2. What is an earthquake? The slipping and breaking of rock material along a fault. Faults are “cracks” in the crust near plate boundaries that are under stress. Stress is caused by the heat within the earth trying to escape and the movement of the plates.

3. Three Types of Faults Strike-Slip - shearing Thrust - Compression Normal – pulling away

4. What causes earthquakes? 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 – kind of bounces back like a rubberband.

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

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

7. Seismic Waves in the Earth http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

8. Primary Waves (P Waves) 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

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

10. Typical Seismogram http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

11. Comparing Seismic Waves

12. Surface Waves Move along the Earth’s surface Produces motion in the upper crust – Motion can be up and down – Motion can be around – Motion can be back and forth 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 The further away an earthquake is, the greater the time between the arrival of the P waves and the S waves

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. Earthquake Waves & Earth’s Interior

18. How Seismographs Work http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM the pendulum remains fixed as the ground moves beneath it

19. How are Earthquakes Measured? Richter Scale

20. 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

21. Tsunamis http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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

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