Plate Tectonics

1. Plate Tectonics Evolution of the Earth Free powerpoints at http://www.worldofteaching.com

2. Interior Inner Core Outer Core Lower Mantle Upper Mantle Crust

3. Interior 2259 km 1220 km 2851 km

4. What’s in the Earth’s Layers: Crust: is made up of Silicates which are cooler-rigid rock Mantle: -made up softer weaker rock that can flowslowly. Core: -Outer core: liquid metal and very hot! -Inner core: solid metal and very high pressure!

5. Volcanoes • Volcanoes are the result of hot spotswithin the crust or mantle of the earth. • The hot, liquid rock will break through weak spots in the surface and form volcanoes or flood basalts. These are called Effusive/Quiet Volcanoes • Many volcanoes do not release lava, instead they spit ash. These are called Explosive Volcanoes • The type of volcano is determined by the materials in it. Go to: http://www.nationalgeographic.com/forcesofnature/interactive/index.html

6. Volcanoes Fill in the following table to determine how quiet and explosive volcanoes differ:

7. Volcanoes Quiet lava flows

8. Volcanoes Mt. St. Helen before the explosive eruption

9. Volcanoes

10. Volcanoes Time lapse of the eruption

11. Volcanoes Mt. St. Helen after the eruption

12. Volcanoes Mt. St. Helens begins the rebuilding process

13. Flood basalts: When volcanic eruptions coats a thick layer of cooled magma over the surface of the earth. This is IGNEOUS ROCK. Igneous Rock is a type of rock that is made in the mantle

14. Volcanoes

15. Where does the energy to make a Volcano come from?

16. The earth’s core is extremely HOT!Magma in the mantle is always moving in the earth because of the Earth’s Core, which causes Convection: Hot materials rise and cool materials sink.

17. This causes the plates to move with the magma of the mantle to:1) move apart (Divergent Boundaries) or • 2) move together (Convergent Boundaries) and even • 3) past one another (Transform Boundaries.)

18. Because Plates move they cause the magma to be released through cracks in the earth’s crust creating volcanoes.

19. Volcano locations:Why at these locations?

20. The answer is Tectonic Plates

21. The reason volcanoes occur at specific locations: 1. Plate Tectonics Move at a Convergent Zone: (together)

22. Convergent Zones: Volcanoes

23. The reason volcanoes occur at specific locations: 2. At Divergent Zones: (a part)

24. Tectonic Plates

25. Tectonic Plates Another source of evidence is based on seafloor ages which get younger as we approach sea floor ridges

26. Pangea • What is Pangaea? • Pangaea was a super continent at one time. • Scientists use the similarity of rock types and fossil types that date to the same age to support their theory that the continents were connected to form a super continent. • The map below give just one example of areas on different continents that show the same fossils and rock types.

27. Pangea

28. Pangea

29. Pangea The break up of Pangea

30. The reason volcanoes occur at specific locations: 3. Magma moves to the surface of the earth near a weak spot and can activate a magma chamber • http://sio.ucsd.edu/volcano/about/magma.html 4. This can happen over a HOTSPOT. The Hawaiian Islands have formed because a plate moved over a hotspot.

31. Mid-Plate Hotspots

32. What types of energy are taking place to have a volcano? • Mechanical Energy: • Magma moves from the interior earth up to a weak portion in the earth’s crust. • Magma also moves out from the volcano. • Ash and rock can also move out from a volcano like in a pyroclastic flow. • Heat Energy • The earth’s core has large amounts of heat that escape at the earth’s surface through a volcano Draw how a volcano works by using words to describe the process such as: magma, crust, mantle, mechanical energy, heat energy

33. Earthquakes • Earthquakes are a result of motionwithin the earth. • This only occurs where the earth is solidand therefore can only occur within about 100 miles of the surface • Earthquakes provide the best evidence regarding the interior structure of the Earth.

34. Earthquakes

35. Earthquakes

36. Earthquakes

37. Earthquakes A. Where the earthquake occurs B. Directly above the earthquake C. Where the land masses move past one another D. Where the land will either drop down, jet up or change along the fault. E. Waves that move outward causing the shaking movement of the earth.

38. Waves fall under two categories: • P-Waves: occurs when fault moves past each other horizontally, cause a compressed wave. • S-Waves: occurs when faults move vertically, causes a wavy wave. * Both display Mechanical Energy!

39. Both Body Waves and Surface Waves will differ in both S & P Waves:

40. Seismograph: Measures movement in the earth.

41. Finding an Earthquake’s Epicenter

42. Earthquakes occur often!

43. Earthquakes occur at plate boundaries more frequently Location of worldwide earthquakes

44. Earthquakes Earthquakes by depth. Notice that the deep earthquakes occur only at subduction zones.

45. The bigger the magnitude of the earthquake, the more mechanical energy there is. • Go to: http://www.nationalgeographic.com/forcesofnature/interactive/index.html • Fill out the following table:

46. Different Forms of Energy In the Earth • Mechanical Energy: Energy due to motion • Heat energy: energy due to heat • Potential energy: energy that is built up but not yet released • Kinetic Energy: energy that is occurring (in motion)

47. Tectonic Plates

48. Tectonic Plates Today plate boundaries are determined by examining the location of volcanoes and earthquakes. Volcanoes result from the friction (heat) of the plates motion. Earthquakes occur where plate rub against one another

49. Plate Boundaries • Convergent – plates move toward one another • Divergent – plates move away from each other • Transform – plate moves sideways from each other

50. Faults occur at these Plate boundaries, where land masses move. These faults when moved release energy in the form of an earthquake.There are 3 different faults: 1. Normal Fault: as stress is pulled away on the plates, one land mass slips down. (Divergent Plate boundary)