• Question: What makes a volcano erupt?

    Asked by morganlouise23 to Hannah, Angus, Simon on 17 Jun 2013. This question was also asked by beccawilko.
    • Photo: Hannah Bentham

      Hannah Bentham answered on 17 Jun 2013:

      Great question.

      Actually, there are many factors that cause volcanoes to erupt, and depends on
      *where the volcano is
      *what type of source it has
      *the chemistry of the magma and the surrounding rock
      *the water content
      *when was the last eruption.

      Volcanoes have magma chambers, which will fill up with magma and then there will be an increase in pressure. When the pressure is so high, the volcano will start to deform, sometimes with a bulge growing on the side of the volcano. Or maybe the volcano will allow gas to escape instead. If the bulge and escape of gas do not relieve enough pressure, the volcano will actually erupt lava, rocks, and great amounts of ash.

      Some volcanoes erupt very often (like in Hawaii – it’s on a hotspot which is constantly fed magma by a big plume) and some remain dormant for many 100s of years.

    • Photo: Angus Ferraro

      Angus Ferraro answered on 27 Jun 2013:

      Hannah’s answer is very good. I don’t have much to add, except that not all volcanic eruptions are explosive. Some of them are rather undramatic. There are volcanoes in Iceland where the lava kind of ‘oozes’ out rather than it erupting properly.

    • Photo: Simon Holyoake

      Simon Holyoake answered on 28 Jun 2013:

      can’t add anything to Hannah or Angus’s answers here!

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