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The Changing Earth

The Changing Earth. Video Clip: Intro - 1:34. http://www.edu.pe.ca/southernkings/Pictures/fault5.gif. Pangaea B6-9. Pangaea in motion. http://www.exploratorium.edu/faultline/earthquakescience/images/pangea_lrg.gif. Pangaea B6-9. one giant land mass of all of the continents

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The Changing Earth

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  1. The Changing Earth Video Clip: Intro - 1:34 http://www.edu.pe.ca/southernkings/Pictures/fault5.gif

  2. PangaeaB6-9 • Pangaea in motion http://www.exploratorium.edu/faultline/earthquakescience/images/pangea_lrg.gif

  3. PangaeaB6-9 • one giant land mass of all of the continents • 200+ million years ago 2:23

  4. The Theory of Continental DriftB10-12 • Alfred Wegener suggested idea that land started as Pangaea, but continents have drifted to their present positions. 3:15

  5. Evidence for Continental DriftB10-15 1. puzzle-piece fit (especially SA/Africa) 2. fossil remains on separate continents 3. same rock layer patterns on separate continents 4. fossils of temperate plants in current polar regions 5. evidence of glaciers in currently warm climates

  6. Earth’s Layers B19 Earth's layers • 1. Crust: the thin, outer layer of Earth • 2. Mantle: hot solid (900-2,000°C) 2,900 km thick • 3. Outer Core: liquid metal (may be iron and nickel) • 4. Inner Core:solid metal (5,000°C in some places) 1:16 http://www.geog.ouc.bc.ca/physgeog/contents/images/earthcut.jpg

  7. 3 Types of Rocks in the Crust website • Igneous – cooled, hardened lava • Sedimentary – layered rock • Metamorphic – igneous and sedimentary rocks that have been CHANGED by heat and pressure

  8. Theory of Plate Tectonics B19-21 & B38-40 • Theory that Earth’s crust is broken into enormous plates that are in motion • Continents still drifting about 10cm/year • Most volcanoes and earthquakes occur at PLATE BOUNDARIES 1:21

  9. Lithosphere & AsthenosphereB38-39 • Lithosphere– crust and upper mantle; solid rock (8-64 km thick) • Asthenosphere – the area of the mantle where the rock is soft and slightly melted • Convection current – churning heating and cooling of magma inside the Earth causing tectonic plates to move (like boiling rice) 1:17

  10. Theory of Plate TectonicsB19-21 Fault = large crack in Earth’s surface due to movement of plates 1:25

  11. Tectonic Plate Movement & Plate BoundariesB40-41

  12. Tectonic Plate Movement B40-41 http://www.mrd.gov.fj/gfiji/geology/educate/platect.html

  13. Mountains B45-50 1 Folded – when masses of rock are squeezed from opposite sides (two plates collide). 2. Fault-Block – when blocks of rock move up or down along a fault. 3. Dome – when the surface is lifted up by magma. 4. Volcanic-magma erupts from opening in Earth’s surface Video Clip: Mountains - 2:46 Mountain Maps http://www.anamericandream.net/testimonials.html

  14. Tallest Mountains B49 Tallest Mountain in the World: Mt. Everest Asia 8,708m Tallest North American Mountain: Mt. McKinley AK 6,096 m http://1.im.cz/n/photo/00/54/08blisj-topsirka.jpg http://www.fostertravel.com/akflyi102web.jpg

  15. Earthquakes B58-61 • vibration of earth caused by release of energy as plates shift past one another • can last for a few minutes • Aftershock - shock that occurs after the initial shock of an earthquake – can be felt many miles away • Earthquake occurrencesUSGS website

  16. Measuring Earthquakes B59-61; B74-75 Richter Scale • used to measure magnitude (amount of energy) of earthquake • Scale of 0-9

  17. Measuring Earthquakes B59-61; B74-75 Seismograph • used to record the intensity, duration, and nature of earthquake waves http://www.isgs.uiuc.edu/earthquakes/Images/ss-80_display_seismograph.jpg

  18. Epicenter and Focus B56 • Epicenter – the place on Earth’s surface directly above the origin of the quake • Focus – The exact location of where the earthquake started (underground) http://www.bedford.k12.ny.us/flhs/science/images/epicenter.jpg

  19. Earthquake Faults B64-65 • Fault – crack in Earth’s crust where movement occurs • Types of faults(only the first 3) • Normal • Reverse • Strike/Slip San Andreas fault ~ California

  20. Final Thoughts on Earthquakes Video Clip: Earthquake – 20:00

  21. TsunamiB76-77 • Created by earthquake under water • Most common along Pacific coastal areas • Large wave of water that builds power as it moves into shallower water • Causes massive destruction • Most recent was Indonesia/Sri Lanka area • 2004 Richter Scale = 9.0 > 280,000 died Video Clip: Tsunami – 43:00

  22. Volcanoes B86-89 • any opening in Earth’s crust through which hot gases, rocks, and melted material erupt. • Magma = melted material contained beneath Earth’s surface • Lava = magma that has reached the earth’s surface [can be higher than 1,100°C (2,000°F)] Video Clip: Volcanoes – 1:00

  23. 4 Steps in a Volcanic EruptionB86 STEPS: 1. High temperatures & pressures deep within Earth cause rock to melt. 2. Magma makes its way toward the Earth’s surface melting surrounding material to form a central pipe. 3. Hot melted material moves through the volcanic vent. 4. Magma turns to lava. website

  24. Ring of Fire B87 Ring of Fire-area along the coastlines of NA/SA and Asia/Australia where there are more than 500 volcanoes Video Clip: Ring of Fire – 0:45

  25. Types of Volcanic ActivityB88 • active – erupts constantly • intermittent – erupt on a regular basis • dormant – volcano that has not erupted in a long time • extinct – no record of volcano ever erupting Mt. St. Helens site

  26. 3 Types of Volcanoes Video Clip: Types of Volcanoes – 4:00

  27. Cinder-Cone VolcanoesB88 • explosive eruptions where layers of cinders land near central vent • small with steep slopes • bowl-shaped craters on top • formed in groups • ex. Paricutin in Mexico Cinder-Cone Volcano

  28. Shield VolcanoesB89 • lava flows quietly from crack • larger with gentle slopes • ex. Mauna Loa (Hawaii) largest volcano Shield Volcano

  29. Composite-Cone VolcanoesB89 • explosive eruptions alternate w/ quieter oozes (mix of the two) • steeper near top, but gentle slopes close to the base • most destructive – often occur w/o warning • ex. Mt. Vesuvius Composite–Cone Volcano

  30. Hot SpotsB102-103 • extremely hot places deep within the Earth’s mantle • blowtorch from below • hot spot does not move, but plates move over it • Ex. Hawaii Video Clip: Hot Spots - 0 Video Clip: Hawaii - 0

  31. CalderaB102-103 • large circular depression formed when part of a volcano collapses

  32. The Changing Earth - Review You will need to know: • Wegener’s theory of continental drift & be able to give reasons to support it • theory of plate tectonics & why the plates move as they do • how to identify the layers of the Earth • the three types of rocks found in the Earth’s crust • the types of plates, their characteristics, & the type of boundaries they have • the types of mountains and their descriptions • the difference between the focus and the epicenter of an earthquake

  33. The Changing Earth - Review 8. the difference between a seismograph and the Richter scale 9. what tsunamis and calderas are 10. the difference between magma and lava 11. where the Ring of Fire is located and how many volcanoes are located there 12. the types of volcanoes and their descriptions 13. the descriptions of the terms for volcanic activity 14. how the islands of Hawaii were formed

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