The restless earth

Structure of the earth
1. Inner core
  1. Solid (iron and nickel)
2. Outer core
  1. Liquid (iron and nickel)
3. Mantle
  1. The dense, mostly solid layer between the outer core and crust (plastic)
4. Crust
  1. Continental
    1. Older, mostly 1,500,000,000
    2. Less dense
    3. Can't sink
    4. Cannot be renewed or destroyed
    5. Mainly granite
    6. 35% surface
  2. Oceanic
    1. Newer, most less than 20,000,000yrs
    2. Denser
    3. Can sink
    4. Can be renewed/destroyed
    5. Mainly basalt
    6. 60% earth's surface
Plate margins
1. Destructive
  1. Subduction
    1. One sinks under another
    2. Pacific + Indo-Australian
  2. Collision
    1. Two continental push into each other
    2. Eurasian + African
2. Constructive
  1. Two plates move away from each other
  2. South American + African
3. Conservative
  1. Two plates slide alongside each other
  2. Pacific + North American
Volcanoes
1. Composite
  1. Eruptions infrequent but often violent
  2. Steep slopes and narrow base
  3. Secondary cones and layers of thick lava and ash
  4. Destructive plate boundaries
2. Shield
  1. Low, rounded peak
  2. Wide base and gentle slopes
  3. Layers of runny lava, little ash
  4. Constructive plate boundaries
  5. Eruptions frequent and not violent
Supervolcanoes
1. A mega colossal volcano that erupts at least 1000km3 of material. (Mt. St. Helens only erupted 1Km3)
2. Large depressions called calderas often marked by a rim of higher land around the edges
3. 1) Rising magma cannot escape and a large bulge appears on the surface
  1. 2) Cracks appear in the surface and gas and ash erupt from the magma chamber
    1. 3) the magma chamber collapses, forming a depression called a caldera
4. Yellowstone effects
  1. National
    1. Destroy 10,000Km2 of land
      1. Kill 87,000 people
    2. 15cm of ash would cover buildings within 1000Km and 1 in 3 die
      1. Ash would affect transport, electricity, water and farming
        Lahars possible
  2. International
    1. UK would receive ash 5 days later
      1. Global climates would change, crops would fail and subsequently many people would die

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The restless earth

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	Created by jeacur over 11 years ago