1. Earthquakes By Mr. D and some slides taken from the USGS

2. Earthquakes usually occur on faults caused by the subduction of two plates

3. Lisa Wald USGS Pasadena U.S. Department of the Interior U.S. Geological Survey USGS Earthquake Hazards Program Plate Tectonics

4. Plate Boundaries

5. Three Types of Faults Strike-Slip Thrust Normal

6. Strike-slip Fault Example

7. Normal Fault Example Dixie Valley-Fairview Peaks, Nevada earthquake December 16, 1954

8. Thrust Fault Example

10. Bigger Faults Make Bigger Earthquakes

11. Bigger Earthquakes Last a Longer Time

12. What Controls the Level of Shaking? Magnitude –More energy released Distance –Shaking decays with distance Local soils –amplify the shaking

13. Is there such a thing as “Earthquake Weather”???

14. Earthquake Effects - Ground Shaking Northridge, CA 1994

15. Earthquake Effects - Ground Shaking KGO-TV News ABC-7 Loma Prieta, CA 1989

16. Earthquake Effects - Surface Faulting Landers, CA 1992

17. Earthquake Effects - Landslides Turnagain Heights, Alaska,1964 (upper left inset); Santa Cruz Mtns, California, 1989 Source: National Geophysical Data Center

18. Earthquake Effects - Fires KGO-TV News ABC-7 Loma Prieta, CA 1989

19. Earthquake Effects - Tsunamis Photograph Credit: Henry Helbush. Source: National Geophysical Data Center 2011 Tsunami in Japan

20. Seismic Waves

21. Richter magnitude scale One way we measure magnitude. Developed in 1935 by Charles Richter in partnership with Beno Gutenberg, both of the California Institute of Technology. An earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0.

22. Earthquake Magnitude

23. Earthquake Magnitude Scale Magnitude Earthquake Effects Estimated 2.5 or less: Usually not felt, but can be recorded by seismograph (frequently occurs in CA). 2.5 to 5.4: Often felt, but only causes minor damage. 5.5 to 6.0: Slight damage to buildings and other structures. 6.1 to 6.9May cause a lot of damage in very populated areas. 7.0 to 7.9: Major earthquake. Serious damage.20 8.0 or greater: Great earthquake. Can totally destroy communities near the epicenter.

24. EPICENTER the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates.

25. Earthquake Location

26. The San Andreas Fault

27. Pacific-North American Plate Boundary

28. Will California eventually fall into the ocean???

29. Why not? The motion between the pacific and the north American plates beneath us is mostly horizontal. That is, the Pacific plate is moving "up" the coast, not away from the North American plate, at a rate of dozens of millimeters per year. So in several million years, residents of San Francisco will see the L.A. skyline out their windows.

30. Faults of Southern California Source: SCEC Data Center

31. Shaking Hazard in Southern California

32. Real-time Earthquake Information

33. Any Questions? Remember you will have a test on this- so ask the questions now before you forget.