• Question: why do volcanoes erupt??

    Asked by zeinab to Sarah, Tim, Tom on 24 Jun 2011.
    • Photo: Sarah Thomas

      Sarah Thomas answered on 23 Jun 2011:

      I think of it like the Earth relieving some pressure!

      The main reason for the eruptions from volcanoes is the heat deep within the Earth’s mantle. This heat slowly melts rocks to create a slow moving substance called magma. Magma is lighter than the solid rock around it so magma rises. After a while the magma pushes through vents and fissures in the earth’s surface. Then a volcanic eruption occurs! The magma comes out of the volcano and is now called lava.

    • Photo: Tom Crick

      Tom Crick answered on 24 Jun 2011:

      A volcano is an opening, or rupture, in a planet’s surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface. Volcanoes are generally found where tectonic plates are diverging or converging.

      The reason why they erupt is due to the enormous pressures of the tectonic plates — when this pressure becomes too great, an eruption occurs and magma is vented.

      Or in the case of the the 2010 eruption of Eyjafjallajökull in Iceland, huge dust clouds!