Supervolcanoes

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  • Topic: Volcano, Yellowstone Caldera, Henry's Fork Caldera
  • Pages : 4 (1503 words )
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  • Published : February 3, 2013
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Supervolcanoes.
Supervolcanoes; their unpredictability and mystery make them into the worst environmental hazards our planet can face in one of their rare but catastrophic eruptions. Our lack of understanding regarding them is the cause for concern, but we cannot understand and predict eruptions, they’re unique according to the scale and other factors. We have some knowledge but due to the fact that no supervolcano has had a full-scale eruption in the past 2,000 years, we can only try to guess the extremity of eruptions through the studies of rocks and fossils from the time. A supervolcano is phenomenally large, around 50 to 100km in diameter on average and has a huge bubble of sticky magma beneath it, tens of kilometres across that is trapped under overlying rock and with gases such as sulphur dioxide, water vapour and carbon dioxide trapped in it.

They are formed near destructive plate boundaries where material from a plate that is descending rises back to the surface, this magma then rises up creating the large bubble of magma below the overlaying rock. They are also formed at continental hotspots, in either situation; the continental crust is being extended locally. This then makes weaknesses that allow the magma plumes to rise over very long periods of time and this process occurring over so much time (in some cases hundreds of thousands of years) is why the magma lakes have such an colossal mass. They erupt around every 50,000 to 100,000 years, in the eruption is over 1,000 cubic km of material that is blasted into the air, this causes unimaginable damage, short and long term.

On the VEI (Volcano Explosivity Index) a supervolcano is the top of the scale. The eruptions can begin in numerous ways: an earthquake could crack the rock above and release the magma, the pressure could push off the rock when it becomes too high or a significant drop in pressure could release the dissolved gases in the magma solution causing an explosive froth to blast out...
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