Glowing cloud

from Wikipedia, the free encyclopedia

A glowing cloud (French nuée ardente ) is a phenomenon that occurs during volcanic eruptions . The term is usually synonymous with pyroclastic flow (French coulée pyroclastique ), which, however, contains more solid, coarse material such as lava and pumice . Clouds of embers emerge when new eruptions arise and move horizontally when they emerge on the flank of the volcanic cone. Pyroclastic currents, on the other hand, often arise at the chimney of a volcano, but can also arise like glowing clouds when a flank erupts, such as the eruption of Mount St. Helens in 1980 .

Ember clouds arise when the chimney of a volcano is clogged with viscous magma and the high pressure inside tears open a flank of the mountain. As a result, very hot gases, magmas, ashes and rocks burst out explosively and devastate their surroundings within minutes. The range is up to 30 kilometers, the affected area up to 600 km². Can glowing clouds speeds of up to 1000 km / h - so close to the speed of sound - and up to 1000 temperatures  ° C reach. They are often viewed as a variant or a more gaseous form of a pyroclastic flow.

A well-known example of glowing clouds is the destruction of Saint-Pierre and the killing of its inhabitants by the Pelé volcano in Martinique on May 8, 1902, which led to the formation of the terms pyroclastic current and glowing cloud.

literature

  • Jens Edelmann: Climb and explore volcanoes. Volcano tours, volcanism, forms of eruption, behavior in the event of a volcanic eruption, rocks and minerals, interesting volcanic areas, tours with children: planning, costs, equipment, safety, photography, sources of information. 2nd updated edition. Reise Know-How Rump, Bielefeld 2007. ISBN 978-3-8317-1625-8 (p. 78).
  • Anke Fischer: Natural disasters . Compact, Munich 2007, ISBN 978-3-8174-6091-5 (p. 22 ff).
  • Hans Füchtbauer (Hrsg.): Sediments and Sedimentgesteine In: Sediment-Petrologie . Part 2, 4th, supplemented and revised edition, Schweizerbart, Stuttgart 1988. ISBN 3-510-65138-3 .
  • Hans-Ulrich Schmincke: Vulcanism . 2nd, revised and expanded edition, Wissenschaftliche Buchgesellschaft, Darmstadt 2000. ISBN 3-534-14102-4 .
  • Martin Rietze: Volcanoes . Introduction to the world of volcanoes, Primusverlag, Darmstadt 2010. ISBN 978-3-89678-836-8 .