Revision for exam!


Restless Earth


Earthquakes are caused by the release of built-up pressure inside the Earth's crust. An earthquake's power is measured on the Richter scaleusing an instrument called a 'seismometer'.An earthquake is the shaking and vibration of the Earth's crust due to movement of the Earth's plates (plate tectonics). Earthquakes can happen along any type of plate boundary

  • short-term (immediate) impacts
  • long-term impacts
  • social impacts (the impact on people)
  • economic impacts (the impact on the wealth of an area)
  • environmental impacts (the impact on the landscape)

MEDC= A more economically developed country

LEDC= A less economically developed country

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The Earth

Cross section showing structure of the Earth (

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Volcanoes and Plate Boundary

Different plate boundaries

  • At a tensionalconstructive or divergent boundary the plates move apart.
  • At a compressional, destructive or convergent boundary the plates move towards each other.
  • At a conservative or transform boundary the plates slide past each other.

    Key facts

    • A volcano is formed by eruptions of lava and ash.
    • Volcanoes are usually cone shaped mountains or hills.
    • When magma reaches the Earth's surface it is called lava. When the lava cools, it forms rock.
    • Volcanic eruptions can happen at destructive and constructive boundaries, but not at conservative boundaries.
    • Some volcanoes happen underwater, along the seabed or ocean floor.
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Shield Volcano

  • Shield volcanoes are usually found at constructive or tensional boundaries.
  • They are low, with gently sloping sides.
  • They are formed by eruptions of thin, runny lava.
  • Eruptions tend to be frequent but relatively gentle. The characteristics of a shield volcano (
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