Encyclopedia

volcano

volcano, vents or fissures in the earth's crust through which gases, molten rock, or lava, and solid fragments are discharged. Their study is called volcanology. The term volcano is commonly applied both to the vent and to the conical mountain (cone) built up around the vent by the erupted rock materials. Volcanoes are described as active, dormant, or extinct. The soil resulting from decomposition of volcanic materials is extremely fertile, and the ash itself is a good polishing and cleansing agent.

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The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2007, Columbia University Press. All rights reserved.

More on volcano from Fact Monster:

  • Volcanoes - One of the most fascinating, if tragic, natural disasters of the last two thousand years occurred on August 24, 79 A.D. On this day, Mount Vesuvius (located near Naples, Italy) erupted, engulfing the nearby cities of Pompeii and Herculaneum in a tremendous flow of cinder, ashes, and mud.
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