1. More Earth Science Landforms Earthquakes Seismic Waves Shadow Zone

2. Landforms

3. Mountains A mass of rock rising more than 600 meters above the surrounding land Relief vs. Elevation

4. Types of Mountains

5. Fold Mountain

6. Fold Mountains Usually made mostly of sedimentary rock folded by compression forces These are the tallest and most common of all mountains

7. Examples of Fold Mountains Appalachian Mountains

8. Rocky Mountains

9. Alps

10. Himalaya Mountains

11. Fault-Block Mountain

12. Fault Block Mountain Ranges are cause by a series of normal faults

13. Examples of Fault block Mountain ranges

14. Sierra Nevada Mountains, CA

15. Grand Tetons, WY

16. Wasatch Mountains, Utah

17. When the Earth SHAKES Earthquakes

18. What causes earthquakes?

19. Volcanic eruptions can cause earthquakes but most earthquakes are caused by FAULTING These are often called TECTONIC earthquakes

20. Theory VS. Law A THEORY is a logical idea that has not been proven directly but it often can be proved mathematically It is a working set of rules that define a body of knowledge A LAW is observable and can be proven- to a point. Nothing is 100% sure in a Universe as vast as ours

21. Elastic Rebound Theory The Elastic Rebound Theory was first proposed by American geologist Harry Fielding Reid after the 1906 San Francisco Earthquake

22. Elastic Rebound The sudden release of progressively stored strain in rocks, resulting in movement along a fault After the stress becomes too great, the rock layers break, vibrating back and forth until eventually coming to a rest

25. As the rock layers are shaking back and forth they send out waves of vibration called Seismic Waves “Seismic” always has to do with earthquake activity

26. Seismic Waves are waves of vibration sent out in all directions from the FOCUS

27. Focus The point below the surface where the rock layers break and move Epicenter The point on the surface, directly above the focus. Where the greatest damage usually occurs

28. Fault Focus Epicenter Seismic Waves

29. Measuring Earthquakes

30. Charles Richter 26 April 1900 – 30 September 1985

31. Seismograph A machine that measures earthquake (seismic) waves

32. Zhang Heng seismograph is almost 2000 yrs old

33. Early Seismograph Operates on the principle of Newton’s First Law

34. Seismogram The recorded information of earthquake waves

35. The Richter Scale is based on MAGNITUDE Seismogram

36. Each # is TEN TIMES larger than the # before it… Magnitude 1 Magnitude 2 Magnitude 3

37. Pennies as an example: Mag. 1 = 1 penny Mag. 2 = 10 pennies Mag 3 = 100 pennies Mag. 4 = 1000 pennies Mag. 5 = 10,000 pennies Mag. 6 = 100,000 pennies Mag. 7 = 1,000,000 pennies Mag. 8 = 10,000,000 pennies Mag. 9 = 100,000,000 pennies Mag. 10 = 1,000,000,000 pennies (that’s $10 million in pennies!!)

38. Richter Magnitudes Earthquake Effects Less than 3.5 Generally not felt 3.5-5.4 Often felt, little damage Under 6.0 Slight damage to buildings 6.1-6.9 Destructive to about 100 km from epicenter 7.0-7.9 Major earthquake. Can cause serious damage 8 or greater Large earthquake. Serious damage for hundreds of km

39. Anatomy of a basic wave

40. Crest – the highest point on a wave (A, F) Trough – the lowest point on a wave (D, I) Amplitude – the distance between the midpoint & crest or trough Wavelength – distance between any two successive points on a wave Frequency - # of vibrations/ second (Hertz)

41. Types of Seismic Waves

42. Body Waves are waves that travel through the body of the earth Surface waves only travel along the surface of earth

43. Body Waves

44. Primary Waves AKA P-Wave Type of Longitudinal Wave Causes back and forth motion Follows the same direction as the energy transfer

45. P-Waves Type of COMPRESSIONAL wave (like sound) Will travel through solid, liquid or gas Travels at: 7.8 – 8.5 kps in mantle 7.2 kps in oceanic crust 3.5 kps in continental crust

46. Primary Wave http://sunshine.chpc.utah.edu/labs/seismic/surface.swf

47. Secondary Wave AKA S-Wave Particle motion is perpendicular to direction of energy transfer Transverse or Shear Wave Will travel only through solids Travels 4 – 5 kps

48. Secondary Wave http://sunshine.chpc.utah.edu/labs/seismic/surface.swf

49. Surface Waves

50. Two main types of surface waves: Love Wave Rayleigh Wave Recent evidence show s that L-Waves attenuate (gradually disappear) more slowly in older rock (eastern US) and more quickly in younger rock (western US)

51. Love Wave http://sunshine.chpc.utah.edu/labs/seismic/surface.swf

52. Love Waves Love Waves travel less than 4 kps Move side-to-side; like a snake Cause the most damage

53. Seismic Waves

55. Seismogram with the P- Wave, S-Wave and L-Wave

56. Seismic Risk in the US

57. Triangulation

58. Refraction

59. Refraction of seismic waves within the Earth

60. Zone between about 105 degrees & 145 degrees is the Shadow Zone

61. 105 degrees 145 degrees Focus

62. Shadow Zone

64. How Hawaiian Islands are formed