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Watch: Earthquakes

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The layers of the Earth

The Earth is made up of different layers:

  • the core at the centre, which is mainly metal
  • the mantle, which is mainly rock
  • the crust, which is the part we can see
A cartoon globe cut open to show the core, crust and mantle.
A cartoon globe with tectonic plates on its surface.

The crust (together with the upper layer of the mantle) is made up of different pieces, called tectonic plates. These plates fit together like a jigsaw and are moving at a rate of a few centimetres a year, in different directions and at different speeds.

A cartoon globe with tectonic plates on its surface.
Arrows on tectonic plates pointing towards each other.

Some plates slide past each other, others move away from each other and some bump into each other.

Sometimes these plates lock together when they meet. This is called a plate boundary or a fault line.

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What are earthquakes?

A diagram of two tectonic plates sliding against each other.
  • As plates move in different directions over long periods of time, friction causes energy to build up.

  • It becomes so great that the energy is released, which creates a shock wave - an earthquake.

A diagram of two tectonic plates sliding against each other.
A diagram of a wave heading towards a city.
  • If an earthquake is beneath the ocean it can create a series of huge waves, called a tsunami.

  • There are thousands of earthquakes across the world each day.

A cartoon of people on computers and machines looking at the Earth.
  • Some are so small that they can only be detected by specialist equipment. Others can be so intense that they can destroy towns and cities.

  • The Richter magnitude scale is used to measure the size of earthquakes.

  • Many earthquakes occur around the Pacific Ocean. People who live there, in countries such as Japan, are used to earthquakes happening. They build earthquake-resistant buildings that sway with the shock waves rather than fall down.

  • Although there are earthquakes in the UK, they are rare and so small that most people do not feel them.

A cartoon of people on computers and machines looking at the Earth.
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Watch: Explain this... Earthquakes

Watch this video from 成人快手 Teach to learn about what causes earthquakes.

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Activity: Quiz 鈥 Earthquakes

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