Falcon Focus

1. Falcon Focus

2. Essential Question

3. Standard 8-3.8 EARTHQUAKES

4. Assessing Prior Knowledge and Relativity • What have you heard about earthquakes lately? • Why should we study earthquakes?

5. Earthquakes!

6. INTRODUCTION • http://video.nationalgeographic.com/video/player/environment/environment-natural-disasters/earthquakes/earthquake-101.html

7. What is an Earthquake? The definition of an earthquake is… vibrationsthat causethe breaking of rocks. These vibrations move in all directions through the earth. They begin at a point along a fault.

8. Earthquakes • If the __pressure___ or stress becomes too great, the rock breaks at a weak point along the fault and ___energy_____ is released

9. Where does an earthquake begin? Epicenter Focus

10. aaALONG THE FAULT

11. Parts of the Earthquake • The energy spreads outward in all directions as vibrations called ____seismic waves_____. • The _focus____ of the earthquake is the point in the crust, or mantle, where energy is released. • The _epicenter___ is the point on Earth’s surface directly above the focus; energy that reaches the surface is greatest at this point.

12. Focus – point inside the Earth where an earthquake beginsEpicenter – point on Earth’s surface above focus

13. Focus, Epicenter, and Fault

14. RECAP • (Take a minute to fill in the blank)

15. ANSWERS • Epicenter: is located right above the focus and has the greatest amount of energy • Focus: releases the energy (seismic waves) • Fault: a break in the Earth’s Crust (is where an earthquake takes place) • Seismic waves: is the energy that is being sent out from the focus

16. Use the words above to Label the Following parts of the earthquake.

17. ANSWERS • A: FOCUS • B: EPICENTER • C: FAULT • D: SEISMIC WAVES

18. Cause of Earthquakes What Causes an Earthquake?  Aftershocks and Foreshocks • An aftershock is a small earthquake that follows the main earthquake. • A foreshock is a small earthquake that often precedes a major earthquake.

19. San Francisco, 1989

20. San Francisco, 1989

21. San Francisco, 1989

22. San Francisco, 1989

23. San Francisco, 1989

24. San Francisco, 1989

25. San Francisco, 1989 …And that was just a 7.2 on the Richter scale!

26. Haiti 2010

29. SEISMIC WAVES • 8-3.2 Explain how scientists use seismic waves – primary, secondary, and surface waves – and Earth’s magnetic fields to determine the internal structure of Earth.

30. 3 TYPES OF SEISMIC WAVES • PRIMARY (P) WAVES • SECONDARY (S) WAVES • SURFACE WAVES CONSIDERED AS BODY WAVES

31. SEISMIC WAVES • _SEISMIC WAVES___ are waves generated by an earthquake that travel through the Earth. These waves can cause the ground to moveforward, backward, up, down, and even to ripple. Seismic Waves are generated at the __SAME___ time but move in different ways, and at different speeds.

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

33. SEISMIC WAVES • Scientists use the principle that the speed and direction of a seismic wave depends on the material it travels through.

34. How does scientist know or study the Earth’s Core? • Because of the behavior of these different waves, scientists have indirect evidence for the solid inner core and liquid outer core of Earth because S waves don’t travel through the outer core because it’s a liquid. Also because earthquake waves travel faster through the mantle than through the crust, scientists know that the mantle is denser than the crust.

35. Seismic Waves

36. PRIMARY (P) WAVE • First Wave to Move out from the earthquake focus, the point where the energy is released • Travel the fastest of the three waves • Push and pull rock creating a back-and-forth motion in the direction the wave is moving • (known as longitudinal or compressional waves)

37. P WAVES • Move through solid and liquid layers of Earth (therefore it can move through all layers)

38. 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

39. Secondary Waves (S Waves) • 2nd wave to Move out from the earthquake focus • Move slower than primary waves • Move at right angles to primary waves causing rocks to move up and down and side to side (known as transverse wave: perpendicular to the wave motion)

40. S WAVES • Can only move through SOLID rock therefore it CAN NOT TRAVEL THROUGH THE OUTER CORE because it is a LIQUID. IT STOPS AT THE OUTER CORE.

41. 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

42. Comparing Seismic Waves

43. SURFACE WAVES • Form when P and S waves reach the surfacee • SLOWEST BUT MOST DESTRUCTIVE • Can cause the ground to shake making rock sway from side to side and roll like an ocean wave

44. SURFACE WAVES • Move through solid and liquid layers of Earth (therefore it can move through all layers)

46. Seismic Waves Paths Through the Earth

47. Earth’s Interior Showing P and S Wave Paths

48. Earthquake Waves & Earth’s Interior

49. 8-3.3 Infer an earthquake’s epicenter from seismographic data.

50. Measuring Earthquakes • The energy spreads outward in all directions as vibrations called ___Seismic Waves____. Seismic waves can be measured and recorded by a ____seismograph_______.