Structure and Motion

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Structure and Motion

• Layers of the Earth

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Video

• Structure of the Earth

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• The Earth is made up of different layers which
  include
• Crust
• Mantle
• Core

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Crust

• The rigid surface of the Earth.
• It can be between 0 to 100 km thick.
• Two types
• Continental Crust
• Thicker parts of the crust, above the ocean.
• Oceanic Crust
• Thinner parts of the crust, under the ocean.

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Crust
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Mantle

• Between the crust and the core.
• It is the largest layer.
• Differences in temperature between the top and
  bottom of the layer create heat currents inside
  the Earth.

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Mantle

• Parts
• Uppermost Mantle
• Rigid part (solid-like).
• Together with the crust, it is called the
  lithosphere.
• Asthenosphere
• Just below uppermost.
• Semi-liquid.
• Hot and slow moving.
• Lower Mantle
• Loose moving.

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Mantle
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Mantle
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Core

• Parts
• Outer Core
• Liquid
• Made of iron, makes it heavy
• Movement of liquids create magnetic field.
• Inner Core
• Solid because of extreme pressure.
• Made of iron and nickel.
• Hotter than surface of the sun.

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How Do We Know?

• The internal structure has never been sampled
  directly
• Humans have never penetrated beneath the crust
• The internal structure of Earth is determined by
  using indirect observations
• Every time there is an earthquake, seismic (waves
  of energy) waves penetrate Earths interior
• Seismic waves change speed, are bent and
  reflected as they move through zones with
  different properties
• Data are analyzed to work out the structure of
  the Earths interior