2. Strain

3. Elastic Rebound

4. Focus (point on surface directly above the focus) (point of rupture)

5. Surface

6. P Waves Fastest waves, first to arrive

7. S Waves Slower waves, second to arrive

8. Surface Waves Slowest waves, last to arrive Orbital motion Do the most damage

9. Seismometer

10. Seismogram

11. Travel-time graph Fit the time difference between the first P-wave and first S-wave in-between the blue curves Read off distance to epicenter

12. Great circles Travel-time graph tells you how far away you are from the epicenter, but not the direction. Need three seisomgraph stations to triangulate the location of the epicenter.

13. Magnitude

14. Intensity Evaluation of the severity of an earthquake at a given location. Variables: 1.Distance from the earthquake 2. Total amount of energy released by the earthquake 3. Material type

15. Liquefaction Water-rich clays liquefy during shaking

16. Mercalli Intensity Scale XII - Damage nearly total. Large rock masses displaced. XI - Rails bent greatly. Underground pipelines completely out of service. X - Most masonry and frame structures destroyed. Some well-built wooden structures and bridges destroyed. Serious damage to dams, dikes, embankments. Large landslides. Rails bent slightly. IX - General Panic. Poor masonry destroyed, ordinary masonry heavily damaged, sometimes with complete collapse, reinforced masonry damaged, general damage to foundations. Frame structures, if not bolted, shifted off foundations. Frames racked. Underground pipes broken. Conspicuous cracks in ground. Liquefaction in areas of sand and mud. VIII - Steering of cars affected. Damage to ordinary masonry, partial collapse. Twisting, fall of chimneys, factory stacks, monuments, towers, elevated tanks. Frame houses moved on foundations if not bolted down; loose panel walls thrown out. Cracks in wet ground and on steep slopes. VII - Difficult to stand. Noticed by car drivers. Furniture broken. Damage to weak masonry, some cracks in ordinary masonry. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones, tiles and unbraced parapets. VI - Felt by all. Persons walk unsteadily. Windows dishes and glasses broken. Pictures off walls. Furniture moved or overturned. Weak plaster and masonry cracked. V - Felt outdoors, sleepers wakened. Liquids disturbed or spilled. Small unstable objects displaced or upset. Pictures move. IV - Hanging objects swing. Windows, doors, dishes rattle. Vibration like passing of heavy truck or jolt like a heavy ball striking the walls. III - Felt indoors. Hanging objects swing. Vibration like passing of light trucks. II - Felt by persons at rest, on upper floors, or favorably placed. I - Not felt. Measures the intensity of a ‘quake relative to a given location away from the epicenter.

17. Earthquake severity

18. Intensity Map

19. 1971 San Fernando Earthquake

20. Magnitude Total amount of energy released by the earthquake Richter Scale

21. Richter Magnitude How many kilograms of TNT would have this much energy? 0 0.6 1.0 20 2.0 600 * Smallest quake people can normally feel 3.0 20 000 * Most people near epicenter feel the quake * Nearly 100,000 occur every year of size 2.5 - 3.0 4.0 60 000 * A small fission atomic bomb * Quakes above 4.5 can cause local damage 5.0 20 000 00 * A standard fission bomb, similar to the first bomb tested in New Mexico, U.S. 6.0 60 000 000 * A hydrogen bomb; can cause great damage locally * About 100 shallow quakes of size 6.0 every year 7.0 20 billion* Major earthquake; about 14 every year * Enough energy to heat New York City for 1 year * Large enough to be detected all over globe 8.0 60 billion * Largest known: 8.9 in Japan and in Chile/Ecuador * San Francisco destroyed by 8.25 in 1906 9.0 20 trillion * Roughly the world’s energy usage in a year Each unit is 32-fold energy increase

22. Earthquake Distribution Map

23. Earthquake Hazards Map

24. Some Famous Earthquakes 1811 New Madrid, Missouri: 7.8-9 1886 Charleston, South Carolina: 6.7 1906 San Francisco, California: 8.3 1964 Anchorage, Alaska: 8.6 1983 Saranac Lake, New York 5.1 1989 Loma Prieta, California: 7.0 1994 Northridge, California: 6.4 1995 Kobe, Japan: 6.8

25. New Madrid

26. San Andreas Fault

30. Alaska

31. 1964 Alaskan Quake

32. Anchorage

33. Tsunami

34. Tsunami Picture Unimak Island, Alaska. Wave moving at 800km/hr, 18m high ??

35. Tsunami Damage Map

43. P wave shadow zone P waves slow down and are refracted in liquids

44. S wave shadow zone S waves do not travel through molten metallic liquids