Q:

How does a volcano erupt?

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Quick Answer

A volcano erupts through the build-up and release of pressure, whether that pressure is of its underlying magma, water or both. This release can be explosive, as it was in the famous eruption of Mt. Vesuvius that destroyed Pompeii, or it can be slow and effusive, as it is in the ongoing formation of the Hawaiian islands.

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Full Answer

An eruption that is caused solely by pressures underneath the Earth is a magmatic eruption. In a phreatic eruption, underground water heated by magma forms compressed steam, fracturing and weakening the surrounding rock and ultimately resulting in an violent explosive eruption. A phreatomagmatic eruption is caused by the interaction of magma and water; as the water cools the magma, the resulting stress fractures destabilize the volcano, leading to an eruption.

Explosive eruptions are marked by the violent release of compressed gas, including steam and sulfuric compounds. An effusive eruption, on the other hand, contains little compressed gas and is marked by the gradual flow of lava to the surface. These are two extremes of a sliding scale, with rare Plinian and Ultra Plinian eruptions as the most explosive and continuous Hawaiian eruptions as the least. In general, the more frequent a volcanic eruption is, the less violent and explosive it is.

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Related Questions

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    When did the first volcano erupt?

    A:

    The first volcano erupted approximately 4.5 billion years ago. This is when the earth first came into existence, and long before the first humans walked the earth, according to Scholastic, Inc.

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    How do you make a volcano erupt without vinegar?

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    To make a volcano erupt without using vinegar, use mint Mentos and a diet soda, like Diet Coke or Diet Pepsi. Add the Mentos to the model volcano first, and then pour in the soda.

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    What makes a volcano erupt?

    A:

    Volcanoes erupt due to pressure that the weight of the rocks puts on the magma and forces it to the surface out any available vent or exit provided to it. The magma is in a reservoir like area under the surface and the pressure from the rocks causes the less dense magma to move into any available crack or fissure that it can reach to try to release in some fashion. The magma can even melt its way to the surface if no exit is available for it at the time.

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    How hot is a volcano?

    A:

    The lava from a volcano ranges in temperature from 570 to 2,120 degrees Fahrenheit. In comparison, water boils at 212 F, and a pizza oven is generally 500 to 600 F.

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