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Earthquakes & Volcanoes

Earthquakes & Volcanoes. The Layers of the Earth. Three Layers: Crust Mantle Core. The Earth ’ s Core. Two layers: Inner Core Outer Core Lithosphere Asthenosphere. Continental Drift. WHO: Alfred Wegner WHEN: 1912 WHAT: Pangea HOW: - Fossils

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Earthquakes & Volcanoes

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  1. Earthquakes & Volcanoes

  2. The Layers of the Earth • Three Layers: • Crust • Mantle • Core

  3. The Earth’s Core • Two layers: • Inner Core • Outer Core • Lithosphere • Asthenosphere

  4. Continental Drift • WHO: Alfred Wegner • WHEN: 1912 • WHAT: Pangea • HOW: - Fossils - Rocks - Glaciers - Polar Regions

  5. Explaining Continental Drift GLACIERS MAGNETIC POLES

  6. Questions that Arose… • No Mechanism • Earth’s spin • Strength of rocks • Wind and Ocean currents • Arthur Holmes • Convection Currents • How plates move • Trench • Ridge

  7. The Jig-Saw Puzzle • Two Types of Plates • Ocean Plates • Thin • Dense • Land Plates • Thick

  8. Sea Floor Spreading • Harry Hess • Ridge  Trench • Robert Dietz • Lithosphere NOT Crust • What are the differences between Wegner’s hypothesis and Hess and Dietz’?

  9. Sea Floor Spreading and Magnetics… • Ocean’s floor and Earth’s magnetic field • Positive Magnetic Anomalies • Negative Magnetic Anomalies

  10. Positive VS. Negative Magnetic Strips

  11. SUBDUCTION • Ocean plate goes under land plate • Pushed into Asthenosphere • Stratovolcanoes • Earthquakes • Edge of plate • Asthenosphere

  12. Plate Boundaries • How are they found? • Earthquake depth • Shallow • Intermediate • Deep

  13. RING OF FIRE • How do the trenches relate to the Ring of Fire?

  14. Plate Boundaries • Plates Moving Away • Divergent Plate Boundary • Plates Moving Toward • Convergent Plate Boundary • Plates Sliding Past • Transform Plate Boundary

  15. Divergent Plate Boundary • “Extensional” • Mid-Atlantic Ridge

  16. Convergent Plate Boundary • “Compressional” • Nazca Plate moving under portion of South American Plate • Why does the Nazca plate move under the South American plate? *HINT* What types of plates are they?

  17. Transform Plate Boundary • Cause Earthquakes • San Andreas fault in California • What two plates cause this fault?

  18. When do Volcanoes Happen? • Divergent Plate Boundaries 2) Convergent Plate Boundary 3) Hot Spots

  19. Hot Spots • Fixed spots • Magma = low pressure + shallow depth • Plate moves • Geologist Tuzo Wilson • Emperor Seamounts

  20. Why and Where???

  21. Speaking of HotSpots…Trip to Yellow Stone anybody? • http://dsc.discovery.com/convergence/supervolcano/interactive/interactive.html

  22. The Low-Down on LAVA Three Types: 1- Pillow -Mid-Ocean Ridges -Why does it form like this? 2- Pahoehoe - Characteristics? - How does it form? 3- Aa - Characteristics? Sub-Glacial Pillow Lava Mauna Ula Coast of Kilauea Mauna Loa

  23. * How do they form? *Where do they go? *How does surrounding rock help? Pahoehoe Lava VS. Aa Lava Lava Tube VS. Lava Channel

  24. Pillow Lava – CoastalFlows • Large front • Lava tubes • Lobes • Foreset beds

  25. Common Volcanoes • Crater Lake • Mount Saint Helen • Una Una

  26. Volcanic Rocks • Intrusive • Granite • Extrusive • Basalt

  27. Volcanic Debris • Bombs • Blocks • Lapilli • Cinders • Ash • Scoria • Pumice • Thread lace scoria • Pele’s Hair • Spatter

  28. Components of a Volcano

  29. Volcanic Landforms SHIELD VOLCANOES • Low viscosity • Thin basalt • Gentle slopes • Mauna Loa • 7.5 miles from vent • Powerline poles

  30. Volcanic Landforms Stratovolcanoes • Andesite and Dacite • High silica = viscous • Gas buildup causes • Violent eruptions • Lots of ash • Subduction zones • Mount Saint Helens

  31. Volcanic Landforms Kohala Cinder Cones • What are they made from? • Height • Fire Fountains Fire Fountain Puu Lilinue , Hawaii

  32. Volcanic Landforms Lava Domes • Steep sides • Highly viscous • What type of volcanoes can these be commonly found in? Mt. Saint Helens Mt. Uzen

  33. Volcanic Landforms Volcanic Spine • Where? • What? • What type of lava? Mount Pelee, Martinique Mt. Saint Helens

  34. Volcanic Landforms Flood Basalts • “Lava Plains” • Flat sheets • Fluid lava • How do these compare to shield volcanoes? Columbia River flood basalts

  35. Volcanic Landforms Composite Volcanoes • Layered • What part is steep? • How is the slope? http://www.gly.fsu.edu/~salters/GLY1000/9Volcanoes/Slide36.jpg

  36. Early Detection?... Tiltmeter

  37. What measures the tilt?

  38. Laser light Where can this be found? How can this be useful? Measures horizontal and vertical distances Benchmarks Leveling E.D.M. Surveys

  39. Global Positioning System • System of: - Orbiting satellites - Receivers on volcanoes - Computers • Time information between satellite and receiver • How does this information help scientists?

  40. What does it measure? How does this help? Harmonic Tremor Fumaroles What is measured? How does this help? Seismicity Gas Geochemistry

  41. Volcanoe Video… • http://news.bbc.co.uk/2/hi/science/nature/4972366.stm

  42. Earthquakes • Vibration and Shaking • Faults • Shock Waves • Elastic Strain

  43. Points to know… • Focus • Epicenter

  44. San Andreas 1906 Loma Prieta 1989 Earthquake History • Northridge 1994

  45. Measuring Earthquakes • Seismograph: • Pen • Rotating Paper Drum • Mercalli Scale • Richter Scale

  46. Fun Facts! • Ringing Church Bells • Heat in Iceland • Nutrients for the Earths Soils

  47. DifferentEarthquake Waves • Primary Wave • Secondary Wave • Rayleigh Wave • Love Wave

  48. Different Faults • Strike-Slip Faults • Thrust/ Reverse Fault • Normal Faults

  49. Earthquake Video • http://news.bbc.co.uk/1/hi/sci/tech/4126809.stm

  50. Why are earthquakes in New York so dangerous? • Population and building structure • Transmission of shaking • Water Pressure -More fires

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