A volcano is an opening in a planet or moon'south crust through which molten rock, hot gases, and other materials erupt. Volcanoes frequently course a loma or mountain equally layers of stone and ash build up from repeated eruptions.

Volcanoes are classified as active, dormant, or extinct. Active volcanoes have a contempo history of eruptions; they are likely to erupt again. Dormant volcanoes have not erupted for a very long fourth dimension only may erupt at a futurity time. Extinct volcanoes are not expected to erupt in the future.

Within an active volcano is a sleeping room in which molten rock, called magma, collects. Pressure builds up within the magma chamber, causing the magma to move through channels in the rock and escape onto the planet's surface. Once it flows onto the surface the magma is known as lava.

Some volcanic eruptions are explosive, while others occur as a boring lava flow. Eruptions tin occur through a main opening at the top of the volcano or through vents that course on the sides. The rate and intensity of eruptions, as well every bit the limerick of the magma, decide the shape of the volcano.

Volcanoes are found on both country and the ocean floor. When volcanoes erupt on the ocean floor, they ofttimes create underwater mountains and mountain ranges as the released lava cools and hardens. Volcanoes on the ocean flooring go islands when the mountains become so large they rise higher up the surface of the bounding main.

Volcanoes

Volcanic eruptions tin create colorful and dramatic displays, such every bit this eruption of this volcano in the Virunga Moutains of the Democratic republic of the congo.

agile volcano

Noun

volcano that has had a recorded eruption since the last glacial period, about 10,000 years ago.

fallow volcano

Noun

volcano that has erupted in the past only is unlikely to erupt shortly.

erupt

Verb

to explode or of a sudden squirt textile.

lava

Noun

molten stone, or magma, that erupts from volcanoes or fissures in the Earth'south surface.

Substantive

molten, or partially melted, rock beneath the World'southward surface.

molten

Adjective

solid material turned to liquid by heat.

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    Tyson Brown, National Geographic Society

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    National Geographic Guild

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    Sarah Appleton, National Geographic Society
    Margot Willis, National Geographic Society

    Last Updated

    Apr 5, 2019

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