Plate tectonics

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Find out how the movement of tectonic plates continues to transform our planet, and why earthquakes and volcanoes are common at their boundaries.

Plate tectonics is the theory that Earth’s outer shell, the lithosphere, is broken up into huge irregularly shaped pieces, tectonic plates, that fit together like a jigsaw. The theory underpins our current understanding of volcanoes, earthquakes, mountain formation and deep-sea trenches.

Transforming Earth's surface

Until around 200 million years ago Earth’s continents all formed one huge supercontinent, Pangaea. Over millions of years the movement of plates, by only a few centimetres each year, has caused this supercontinent to separate, forming the continents we have today.

The movement of tectonic plates is caused by heat radiating from within the Earth. There are three types of movement: divergent (plates moving apart), convergent (plates moving together) and transform (plates grinding past each other). These plate interactions explain earthquakes and volcanic eruptions and how mountains and deep sea trenches form.