- Volcanic crater
A volcanic crater is a circular depression in the ground caused by volcanic activity. [cite web
title=Glossary of Terms: C
accessdate=2008-04-12] It is typically a basin, circular in form within which occurs a vent (or vents) from which
magmaerupts as gases, lava, and ejecta. A crater can be of large dimensions, and sometimes of great depth. During certain types of climactic eruptions, the volcano's magma chambermay empty enough for an area above it to subside, forming what may appear to be a crater but is actually known as a caldera.
In the majority of typical volcanoes, the crater is situated atop the mountain formed from the erupted volcanic deposits such as
lava flows and tephra. Volcanoes that terminate in such a summit crater are usually of a conical form. Other volcanic craters may be found on the flanks of volcanoes, and these are commonly referred to as flank craters. Some volcanic craters may fill either fully or partially with rain and/or melted snow, forming a crater lake.
Some volcanoes, such as
maars, consist of a crater alone, with scarcely any mountain at all. These volcanic explosion craters are formed when magma rises through water-saturated rocks and causes a phreatic eruption. Volcanic craters from phreatic eruptions often occur on plains away from other obvious volcanoes.
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volcanic crater — A basin like, rimmed structure, usually at the summit of a volcanic cone. It may be formed by collapse, by an explosive eruption or by the gradual accumulation of pyroclastic material into a surrounding rim. Compare: caldera. GG … Glossary of landform and geologic terms
volcanic crater — noun a bowl shaped geological formation at the top of a volcano • Syn: ↑crater • Hypernyms: ↑geological formation, ↑formation • Hyponyms: ↑caldera, ↑maar • … Useful english dictionary
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Crater — may refer to: In landforms: Impact crater, caused by two celestial bodies impacting each other, such as a meteorite hitting a planet Volcanic crater or caldera, formed by volcanic activity Subsidence crater, from an underground (usually nuclear)… … Wikipedia
crater — [ volcanic ] see volcanic crater … Glossary of landform and geologic terms
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crater lake — a body of water occupying a roughly circular, steep sided volcanic crater or caldera. [1875 80] … Useful english dictionary
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