• Question: how do volcanos explode

    Asked by epee532beak54 on 23 Feb 2026. This question was also asked by gawp532gybe96.
    • Photo: Michael Gillin

      Michael Gillin answered on 23 Feb 2026:

      Volcanoes explode because of pressure building up underground.

      Deep inside the Earth, rock is so hot that it melts into a thick liquid called magma, which contains dissolved gases (kind of like Coca Cola or Pepsi).

      As magma rises to the surface, the pressure from the surrounding rock decreases, dissolved gases form bubbles, and the bubbles quickly expand. If the magma is thick, the gas gets trapped, and the pressure builds until it erupts from a volcano. This often leads to an explosion that releases lava, ash, and rocks.

      However, if the magma is runnier, as in Iceland, the gas escapes more easily, and the volcano is more likely to have a gentle lava flow rather than a big explosion.

    • Photo: Caroline Roche

      Caroline Roche answered on 24 Feb 2026:

      Volcanoes explode or erupt because of a build up of pressure underground.
      An example of a really explosive eruption is Mount St. Helens in 1980, there is even a video showing it.

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