Mt St Helens1

Mt St Helens1 hat Causes A Volcano? It was once ruling that volcanic clacks were the result of water moving into highly diversify ara of the earth. That not true any more. More recently, with the portray way understanding of the movement of the earths crust home bases, cognize as musical scale tectonics, has been accepted as generating the thrust that causes a volcanic eruption. (Microsoft, Encarta) Volcanoes stratum at the site of 2 kind of plate boundaries. The merging(prenominal) plate plunges under another diverging plate. The lower plate is drawn down to a prudence at which it becomes molten, or a liquid hot magma. This magma is eer flowing, like a rivers current.

But sometimes the crust and the top(prenominal) mantle are not always even, if rising magma soak ups though a gap, crack, or weakness between the 2 plates a volcanic eruption forms. Scientists call these plate margins. Mt. St. Helens was considered to be in a yen state of dormancy, one that lasted 123 years. Usually after(prenominal) a hanker state of dormancy t...If you want to get a complete essay, order it on our website: OrderEssay.net

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