volcanoes and earthquakes

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volcanoes and earthquakes

where plates meet, volcanoes and earthquakes occur.

volcanoes are found at destructive and constructive plate margins only.

1) at detructive plate margins the oceanic plate goes under the continental plate because it is more dense.

  • the oceanic plate moves down into the mantle, where its melted and destroyed.
  • a pool of magma forms
  • the magma rises through cracks in the crust called vents.
  • the magma erupts onto the urface (where its called lava) forming a volcano.

2) at constructive margins  the magma rises up into the gap created by the plates moving apart, forming a volcano.

3) some volcanoes also form over parts of the mantle that are really hot (called hotspots) e.g. in hawaii

4) when a volcano erupts, it emits lava andgases. some volcanoes emit lots of ash, which can cover land and block out the sun and form pyroclastic flows (super heated currents of gas,ash and rock.

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