• Question: Why do volcano's sometimes go extinct or dormant ?

    Asked by superian to Angela, Gabriele, Karen, Maria, Shane on 12 Nov 2013.
    • Photo: Karen McCarthy

      Karen McCarthy answered on 12 Nov 2013:

      Well the main reason volcanos go dormant is they run out of magma, which originates from the Earth’s core. Because the continents are always very very slowly drifting, volcanos can drift, even slightly, away from their magma source, meaning they can become dormant. This also means if other once dormant volcano drift over areas where magma is available, then they can become active again and vice versa

    • Photo: Shane Mc Guinness

      Shane Mc Guinness answered on 12 Nov 2013:

      Spot on. Magma fills the area under the plate which make up the earth’s crust. It’s everywhere! Volcanoes occur where the floating on top of this magma meet and separate. But it needs the magma to be flowing upwards towards the crust (it flows just like the air currents in the sky). When these joins in the plates meet an upwelling of magma they create a volcano! And when the plates move along in a different direction they make another volcano cone. Look at some strings of islands in the middle of oceans, like Hawaii. That’s exactly how they’re created! A volcano goes dormant when the flow of magma slows down, but the volcano could still could become active again. However, when the plate moves away from the upwelling, the volcano becomes extinct. Did you know that the Wicklow Mountains were formed like this but are now extinct!? And some were as high as Mount Everest!

    • Photo: Angela Stevenson

      Angela Stevenson answered on 13 Nov 2013:

      Volcano’s are really cool to see in real life! I hiked up to the top of one once. They are also very interesting, so lets learn a bit about them. There are three levels of activity exist for volcanoes: active (still erupting), dormant (not erupting but will eventually blow), and extinct (has not erupted in over 10,000 years). First, lets look at the three main parts of the planet – we ll need this to understand volcano extinction and dormancy. Earth has the core (innermost layer), mantle, and crust (outermost layer). The core is full of magma, and sometimes it makes it up to the mantle and leaks up and surfaces in places where the crust is weak or fractured. That’s where we find volcanoes. The plates of the Earths crust often shift around and if one moves above the mantle, sometimes the magma leak gets cut off, therefore making the volcano extinct. This is actually how the Hawaiian islands came about. Notice that they are aligned in a semi-circular manner? that’s because they are made up entirely of volcanoes, and as the plate that they are on shifts, so does the spot where the island is growing. Hope that helps!

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