What are tectonic plates

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1st Feb 2006
Tectonic Plates

• What are tectonic plates?
• How tectonic plates cause
• and

earthquakes
volcanoes
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Crust
Lithosphere
Mantle
Liquid outer Core
Solid inner Core
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Lithosphere

• This is the crust and the top section of the
  mantle

back
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Tectonic Plates

• This is called PLATE TECTONICS

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Tectonic Plates
Tectonic plate
Why do the plates move??
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Demo

• Watch the demonstration

• How does the purple crystal move?

• This is called convection (heat rises)

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Convection Currents
There are convection currents going on inside the
Earth
The heat from radiation travels up, cools, then
moves back down
It is replaced by more heat and the cycle
continues

• This causes the plates to move a few cms a year

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Earthquakes in the Bay Area
But they are clustered along the Pacific Coast.
Why?
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Moving Plates

• Some plates move together.
• These occur where large mountains form, like the
  Himalayas
• Volcanoes and Earthquakes occur on these plate
  boundaries.

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Earthquakes

• The plates can slide,

This causes a strain on the crust
When this energy is released, earthquakes occur
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Mountains

• Sometimes, the plates hit head on, and form huge
  mountain ranges, like this

• This is how the Himalayas formed.

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Volcanoes
Plates collide
The thin plate is forced below the thick plate
Where the plates hit, mountains or volcanoes
occur
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