1. EARTHQUAKES 1988 Armenian Earthquake – Spitak Communications Building USGS

2. EARTHQUAKES Occur in all plate boundaries  Diverging  Converging  Continent/ocean (Subduction)  Ocean/ocean (Subduction)  Continent/continent (Collision)  Transform

3. PLATE BOUNDARIES

4. WORLD WIDE DISTRIBUTION OF EARTHQUAKES

5. Earthquakes Terms  Focus – point within the earth where initial slip is generated  Epicenter – point on the earth’s surface directly above the focus  Seismic waves - move outward from focus

6. SEISMIC WAVES

7. P-WAVE (Primary)  Fastest seismic  Travels through liquids and solids inside the Earth  Compresses and expands in the direction of wave movement. Tasa

8. S-WAVE (Secondary)  2 nd fastest  Travels through solids inside the earth  Moves with a shearing motion perpendicular to wave travel TASA

9. SURFACE WAVES  Slowest wave  Travels on the earth’s surface  Moves with an elliptical motion or shearing  Potentially most destructive TASA

10. Earthquake Waves

11. MEASURING EARTHQUAKES TASA

12. Seismograph

13. SEISMIC WAVE – TRAVEL TIME Amount of time between P and S waves are directly related to distance to the epicenter Tarbuck &Lutgens

15. LOCATING AN EARTHQUAKE 3 Seismic Stations Required Press & Siever

16. MEASURING EARTHQUAKES INTENSITY (EFFECTS)  Modified Mercalli Intensity Scale Measures damage produced by anearthquake  Useful for:  historic quakes  earthquake engineering  pin-pointing damaged localities Guiseppe Mercalli 1850-1914

18. What affects intensity?  Amount of energy released in the earthquake  Distance from the epicenter  Type of bedrock  Population density  Building construction 1989 Loma Prieta Earthquake USGS

19. MEASURING EARTHQUAKES MAGNITUDE (Wave Amplitude)  Richter Scale – based on largest amplitude of a seismic wave from seismograph during an earthquake  An increase by 1 in magnitude equals 10x magnitude equals 10x increase in amplitude increase in amplitude  Measure of the amount of energy released  Energy released increases 32 x’s for each unit Charles Richter 1900-1985

21. Earthquake Energy Equivalents Education and Outreach IRIS Consortium: www.iris.edu

22. MEASURING EARTHQUAKES MOMENT MAGNITUDE  More accurate than Richter Scale  Estimates total amount of energy released  Takes into account several factors  Displacement along fault  Area of ruptured surface  Strength of underlying rock  More precisely measures large earthquakes, similar magnitudes earthquakes, similar magnitudes as Richter for smaller quakes as Richter for smaller quakes  Can be verified by field studies of fault displacement measurements fault displacement measurements

23. EARTHQUAKE HAZARDS  Ground shaking  Liquefaction  Fire  Subsidence & uplift  Landslides & avalanches  Tsunamis Mexico City Earthquake, September 19, 1985 USGS

24. Earthquake Hazard GROUNDSHAKING  Strain accumulation  One side of the fault is moving in opposition to the other side of the fault  Result: ground cracks and structures collapse Mexico City Earthquake, 1985 Oklahoma University

25. Ground Shaking and Cracking San Francisco Earthquake 1906 G.K. Gilbert

26. 1992 - Landers, CA - 7.5 M Earthquake

27. Kobe, Japan  January 17, 1995  6.9M Press & Siever

28. Kobe, Japan  Expressway fell on it’s side  6308 killed Press & Siever

29. Tohoku, Japan March 11,2011 Magnitude 9.0  401 aftershocks  4 foreshocks  18,000+ killed

30. Ground Shaking Material Amplification  Surface waves are relatively small in solid crystalline bedrock  Surface waves amplify (increase) in poorly consolidated sediments Prentice Hall

31. Mexico City Earthquake, 1985 City built on lake sediments that amplified seismic waves

32. 1985 Mexico City Earthquake - M 8.1

33. Earthquake Hazard LIQUEFACTION  Sand grains saturated with water shake  Sand grains are detached  Sand is unable to support overlying weight of buildings Niigata, Japan 1964 Karl V. Steinbrugge

34. LIQUEFACTION Marina District in San Francisco Loma Prieta Earthquake – 1989 M 7.1

35. Nimitz Freeway 1989 Loma Prieta Earthquake – M 7.1 Dennis Laduzinski

36. Earthquake Hazard FIRE Causes:  Gas mains break  Gas stoves, water heaters, etc. in homes  Inadequate water supply  Firefighters can’t reach fire  Blasting sometimes used to create a fire break Kobe, Japan 1995San Franscico, 1906

37. Fire San Francisco Earthquake 1906  April 18, 1906  5:15 am  Shaking lasted about 1 minute  700-3000 killed  8.3M estimated  $400 million in damages (Image © Archive Photos)

38. Earthquake Hazard SUBSIDENCE & UPLIFT Alaska Earthquake 1964 Prince William Sound Fault Scarp of 16 feet USGS

39. Earthquake Hazard LANDSLIDES & AVALANCHES  Unstable material shaken loose  Rock, sediment or ice  Steep slopes 2002 Alaska Earthquake

40. Yungay, Peru  8 M earthquake  20,000 killed in Yungay  50,000 more killed elsewhere Overlandy.com about 2003

41. Earthquake Hazard TSUNAMIS Seismic Sea Wave Causes:  Submarine landslide  Fault displacement  Volcanic eruption TASA

42. Tsunami

43. Tsunamis in the Pacific

44. Hilo, Hawaii April 1, 1946 – 159 Deaths NOAA

45. Indian Ocean Tsunami Natl. Inst. of Advanced Industrial Science & Technology NOAA

46. Indian Ocean Tsunami Dec. 26, 2004 Banda Aceh, Sumatra Reuters Patong Beach, Phuket

47. Banda Aceh, 2004 Tsunami

48. Japan, 2011 Tsunami videovideo2 videovideo2 video1

49. HAZARD ASSESSMENT  Develop understanding of the earthquake source  Determine earthquake potential  Predict effects of earthquakes  Apply research results Coalinga, CA 1983 Earthquake USGS

50. Shaking Hazard Map

51. World Seismic Hazard Press & Siever

52. San Andreas Fault south of San Francisco R.E. Wallace, USGS

53. EARTHQUAKE PREDICTION (when) verses EARTHQUAKE FORCASTING (where)

54. Earthquake Studies  Tilt of rocks  Swarms of micro- earthquakes  Groundwater changes  Radio Waves  Creep verses locked faults  Foreshocks/Aftershocks  Animal behavior  and more... Parkfield, CA - SAFOD San Andreas Fault Observatory at Depth USGS

55. Parkfield, CA Earthquake Capitol of the World 6M earthquakes - 21 year average 18811901192219341966 1992 (4.5 M) 1994 (5 M) 2004!

56. Earthquake Probability San Andreas Fault

57. Chinese Predict Haicheng Earthquake February 1975 Prediction based on:  Foreshocks  Many large foreshocks before main event  Animal Behavior  Snakes came out of hibernation  Rats scurried around  Large farm animals behaved differently near epicenter Collapsed Factory China Virtual Earthquake Museum

58. Chinese fail to predict Tangshan Earthquake July 28, 1976  2 nd most devastating earthquake in history (worst was also in China 1556, 830,000 died)  8.2 M  750,000 died  No foreshock events ChinaStock