Q:

How does a volcano form?

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Quick Answer

A volcano forms when a vent in the Earth's crust allows magma to well up from below. The magma fills a void underneath the surface, and when it builds up enough pressure, it bursts through to the surface. As the magma cools, it hardens into rock, and multiple eruptions may build up the mountainous form of a volcano.

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How does a volcano form?
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Full Answer

The Earth's crust seems solid, but it is actually made up of 17 large, rigid plates floating over a hot, malleable sea of molten rock. When these plates collide or pull apart, they can allow this molten material, called magma, to make its way upward into the crust. If magma finds a particularly weak spot, it may burst through to the surface, creating a volcano. These can come about as the result of a slow accretion of cooling lava, or they can be the result of spectacular, pressurized explosions.

In some cases, a single vent may create multiple volcanoes. The Hawaiian Islands are the result of a tectonic plate passing over a particular hot spot in the mantle, and that hot spot has created several volcanic mountains in the sea floor. The chain of islands and mountains created by this vent extends as far as Midway, and Kilauea is the current site of the active volcano.

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Related Questions

  • Q:

    What is a main vent in a volcano?

    A:

    The main vent of a volcano is the outlet chamber in the Earth's crust that allows hot magma to reach the surface. While secondary vents may form to alleviate the pressure caused by a magma chamber, the main vent is responsible for giving volcanoes their familiar cone shape.

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  • Q:

    What erupts from a volcano?

    A:

    When a volcano erupts, magma from beneath the Earth is forced out of the volcano's mouth in the form of molten lava. Large amounts of gases and ash can also be released with the lava, depending on the type of eruption.

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  • Q:

    What is a volcanic neck?

    A:

    A volcanic neck, also called a lava neck or volcanic plug, is a cylindrical-shaped volcanic landform created when magma hardens inside the vent of a volcano, according to the University of Wisconsin. Examples of volcanic necks include Devil's Tower in Wyoming, Lizard Head in Colorado and Morro Rock in California.

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  • Q:

    What is a side vent in a volcano?

    A:

    Side vents, also known as secondary vents, in a volcano allow some of the magma and gases to escape but are not the main vent where the eruption takes place. One of the volcano's most recognized characteristic is the crater, but this hole actually forms after the eruption has taken place.

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