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:

    Why do volcanoes erupt?

    A:

    Hot melted rocks collect under the Earth's surface and when the pressure becomes too hard, the Earth's skin breaks, and a volcano erupts. The melted rock inside the Earth is called magma, but when it comes out in an eruption, it is called lava.

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  • Q:

    What do volcanologists wear?

    A:

    Volcanologists wear heavy boots, long-sleeved shirts and heavy work gloves in order to protect their bodies from lava near a volcano. According to Oregon State University, volcanologists might also wear jeans, a rock-climbing helmet for protection and a gas mask.

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  • Q:

    What does the inside of a volcano look like?

    A:

    The inside of a volcano has one or more vents through which gas and lava flow during eruptions. Below the vent is the magma, which is the molten rock that flows upward due to the divergence or convergence of tectonic plates in the Earth's crust. The number of vents and shape of the buildup of magma inside the magma chamber depends upon the type of volcano.

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  • Q:

    What type of volcano is Oshima?

    A:

    Oshima as an island stratovolcano with a large caldera on its summit. Stratovolcanoes are conical volcanoes built up by many layers of hardened lava and volcanic ash, with steep profiles and periodic eruptions.

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