A volcano is an opening in a planet or moon's crust through which molten rock, hot gases, and other materials erupt. Volcanoes oftentimes grade a hill or mountain as layers of rock 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 time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.

Inside an active volcano is a chamber in which molten rock, called magma, collects. Pressure builds upwards inside the magma chamber, causing the magma to motion 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 can occur through a main opening at the top of the volcano or through vents that form on the sides. The rate and intensity of eruptions, as well as the composition of the magma, determine the shape of the volcano.

Volcanoes are plant on both land and the sea floor. When volcanoes erupt on the body of water floor, they ofttimes create underwater mountains and mountain ranges every bit the released lava cools and hardens. Volcanoes on the ocean floor become islands when the mountains become so big they rise above the surface of the ocean.

Volcanoes

Volcanic eruptions can create colorful and dramatic displays, such every bit this eruption of this volcano in the Virunga Moutains of the Autonomous Democracy of the Congo.

agile volcano

Noun

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

dormant volcano

Noun

volcano that has erupted in the by but is unlikely to erupt before long.

erupt

Verb

to explode or all of a sudden eject material.

lava

Noun

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

Substantive

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

molten

Describing word

solid material turned to liquid past rut.

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    Managing director

    Tyson Dark-brown, National Geographic Guild

    Author

    National Geographic Society

    Production Managers

    Gina Borgia, National Geographic Society
    Jeanna Sullivan, National Geographic Club

    Plan Specialists

    Sarah Appleton, National Geographic Gild
    Margot Willis, National Geographic Social club

    Last Updated

    April 5, 2019

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