Understanding Earth's Interior: Layers, Plate Tectonics, and Volcanic Activity

1. Earth’s Interior

2. Lithosphere Solid topmost part of Earth Broken up into large sections called plate Asthenosphere Upper edge of Mantle plasticity

3. Crust • Igneous, Sedimentary & Metamorphic rock • Silicon, Iron, Magnesium, oxygen, aluminum, calcium, sodium, potassium • Solid • Ocean crust less than 10 km thick • Continental crust 32 to 70 Km thick

4. Mantle • Silicon, oxygen, iron, & magnesium • Liquid that shows plasticity • 870 to 2200 degrees Celsius • Radius = 2900 Km • About 70 Km below surface • 80% of Earth’s Volume & 68% of Earth’s Mass • Moho – 1909 Abdrija Mohorovicic • Above Mantle about 32 to 64 Km below surface of Earth

5. Inner Core Iron & nickel Solid 5000 degrees Celsius Radius = 1300 Km 5150 Km below surface Outer Core Around inner core Iron & nickel liquid 2200 to 5000 degrees Celsius Radius = 2250 Km 2900 Km below surface Earth’s Core

6. Plate Tectonics Pangaea Continental Drift – Alfred Wegener Evidence Fossils Continent shapes Rock formation on different continents Mineral and rock deposits (salt, limestone, glacial deposits) Coral reefs Swamps, oil deposits

7. Ocean-Floor Spreading Ocean crust younger than continent crust…? Ocean floor being subducted under continents Midocean ridges Rocks younger at center/ridges

8. Magnetic Stripes in Ocean-Floor • In molten rock magnetic minerals line up w/ the poles • Molten rock hardens leaving solid magnetic evidence • Scientists have discovered that the pole have switched over the past 3.5 million years because the magnetic stripes switch over

9. Magnetic stripes match on opposite sides of the mid-ocean ridge showing that both sides have changed at the same rate…giving more proof of sea floor spreading.

10. Convection Currents Movement of material due to a difference in temperature Lab & overhead…

11. Earth’s Moving Plates Theory of Plate tectonics links continental drift and ocean-floor spreading 7 major lithosphere plates and many smaller ones (pg 65 & overhead) Plates all move in different directions and at different speeds

12. Plate Boundaries

13. Plate Boundaries • Divergent – constructive • Convergent – destructive • 2 ocean plates – older subducted • Ocean plate – continent – ocean plate is subducted and continental plate folds some • 2 continental plates – continents fold up into mts (appalachian, himalayan…) • Strike-slip – conservative

14. Divergent Boundaries Iceland

16. Strike-Slip

17. Plate Changes Plates fuse together Plates change direction New divergent boundaries form Plates can completely be subducted and disappear

18. New Ocean in Africa http://www.cbsnews.com/stories/2005/12/10/tech/main1115779.shtml

19. Earthquakes and Volcanoes

20. Active Volcanoes

21. Pompeii

22. Mt St. Helens – pg 43

23. Iceland April 2010

33. Volcanoes Formed when molten rock (magma) emerges through an opening, or vent, from Earth’s interior (above or below water) Lava = magma forced out of Earth’s interior Accumulation of volcanic lava and rock debris = a cone, dome shaped structure

34. Volcano Terms Crater = steep, funnel shaped depression at top of volcano Caldera = larger depression formed when crater collapses Cinder cone = tall, steep, explosive eruptions Shield volcano = large, gentle slope, quiet lava flows Composite volcano = alternate explosive eruptions & gentle lava flows

37. Volcanic Eruptions‘ • Gases – water vapor, carbon dioxide, hydrogen sulfide, chlorine, fluorine, boron • Liquids – lava • Solids – (pyroclastics – solid magma) ash bombs

38. Volcanic Activity • Active volcano – erupts continually or periodically • Dormant – currently not active, but known to have erupted in modern history • Extinct – not known to have erupted in modern history • Most activity occurs at plates boundaries • Ring of fire = circle around Pacific Ocean • Middle of Atlantic Ocean, and near Mediterranean Sea

40. Yellowstone Caldera

41. Area of Immediate Damage

42. Yellowstone Geological Sites

45. Volcanic Geological Situations Two plates converge beneath an ocean, one plate goes beneath and melts = Aleutian Islands Mid-ocean ridge – two plates separate as molten material pushes up between Ocean plate moves beneath continent plate and melts = Cascade mts in Pacific NW

46. Hot spots Hawaiian Islands “hot spot” beneath crust push magma up creating volcanoes  islands

47. Volcanic Impact Most people die from burns and/or suffocating Habitat destruction (human and wildlife) Natural resourse destruction Agricultural destruction Cleanup… Thermal energy, nitrogen….

48. Surtsey 1963 - 2007

50. On November 14, 1963, an Icelandic fisherman noticed a plume of smoke rising from the open water. Within a day, Surtsey, a new volcanic island, had formed off the southern coast of Iceland from an undersea   eruption that originated at a 130 meter depth. An island eventually rose to a height of 169 metres above sea level that had   an area of 2,5km². This island was named Surtsey for Surtur, the fire   possessing giant of Norse mythology who would set fire to the earth at the   Last Judgment.For three and a half years Surtsey rumbled and lava flowed. Long before the   eruption stopped the island was proclaimed a nature preserve and all travel   there was restricted to scientist that used this unique opportunity to study   the gradual development of life on a sterile landmass.