Why do volcanoes erupt? - Extra Education

 Why do volcanoes erupt?

A volcano erupts due to the degassing of magma. 

 

Magma is a thick mass of molten rock with gases and water vapor. It accumulates in what are called magma pockets, which form as a result of the movement of lithospheric plates. They are most likely to be located along the collision line of the plates. 

 

If liquid magma erupts to the Earth's surface, a volcanic eruption begins. Frequently, a volcanic eruption is accompanied by powerful explosions; these are caused by the degassing of magma and the explosion of combustible gases.