|of these articles is concerned with the geological structure volcano, further meanings under volcano (term clarifying)|
a volcano is a geological structure, which develops, if magma (melted rock) to to thoseSurface of a planet (z. B. the earth) ascends. One calls all accompaniments, which are connected with the withdrawal of the glow-liquid rock melt, volcanism.
In a depth starting from 100 km, in which temperatures between 1000 and 1300 degrees Celsius prevail, rocks melt themselves to tough-plastic magma, in large, drop-shaped herds of magmain 2 to 50 km depth collects. If the pressure becomes too large, the magma ascends over columns and gaps of the lithosphere . Magma, which arrives in this way at the earth's surface, is called lava.
With a volcanic eruption becomenot only glow-liquid, but also firm or gaseous materials set free (volcanism).
of 6 Web on the left of volcanic types after its outside form and after thatKind of their magma supply system partition.
- Partitioning after the outside form:
approx. 95% of the volcanos on earth are layer volcanos. On the other hand are approx. 90% of all active volcanos of sign volcanos.
volcanos can one also after its activity arrange in
- active volcanos (active volcanism)
- inactive volcanos (no active volcanism, are however given conditions for renewed activity)
- extinct volcanos(by missing magma supply no more activity possible)
another possibility of classifying volcanos is, to describe them according to the type of the magma that both the developing form of the volcano and the outbreak behavior crucially certainly:
In summary one can say that “grey volcanos” form “layer volcanos”, while “red volcanos” bring “sign volcanos out”.
Distribution of volcanos
- Volcanos of the spreading zones lie with few exceptions on thatSea-bottom, where the ground plates drift apart.
The magma occurring there is basaltisch. To it mainly red volcanos or sign volcanos belong.
- Volcanos of the Subduktionszonen are the most visible volcanos. They arise, where ground plates one on the other meet and the one ground plate under the other oneone pushes. That abbott-also-ends (often SiO 2 - is enough) rock in the depth is melted and rises, since it has a smaller density, upward, where it comes to eruptions. For this one counts mainly grey volcanos or layer volcanos.
- Volcanos over Hot Spots (also plume or Plutone called) are rare, since it determined world-wide to time only about 40 clearly “Hot Spots “gives (see also: List of identified Hot Spots). A “Hot Spot” is over long time (usually over100 millions Years) stationary melting range in the Earth's mantle under the lithosphere. Since the plates of the lithosphere push themselves during these long periods in the process of plate tectonics over a “Hot Spot” away, bead cord-like one behind the other new volcanos form, thus as became themthrough-weld by the crust. Most well-known example are the Hawaii - islands: the Hauptinsel Hawai'i, which lies as the youngest volcanic island over the “Hot Spot”, is only 400,000 years old, while the oldest of the 6 volcanic islands Kauai in the northwest already forwardsabout 5.1 million years originated in. A further example of this rare kind of volcanism is in the German volcanic Eifel.
Forecast of volcanic eruptions
whether a volcano finally expired or perhaps again activelywill can, particularly interest humans, who live in the environment of a volcano. In each case a volcanic eruption has extensive consequences, because beyond the personal fate infrastructure and economics of the region concerned are lastingly affected. Therefore it is thatpriority aim of research to be able to predict volcanic eruptions as precisely as possible. Fehlprognosen would be alone devastating under cost criteria (evacuation thousands of humans, quiet putting of the entire economic life u.v.m.).
Despite certain thing in common no volcano in its outbreak behavior resembles the other one. Therefore are observations over dwell phasesor seismic activities of a volcano hardly transferably to another.
Deformations are more expressivethe earth's crust directly over the magma stove. With laser measurement the smallest distance changes are seized. So both directly before the outbreak of the Mount Saint Helens has itself 1980 and before the outbreak of the Pinatubo 1991 the earth over the magma stovebulged. Thus the Vulkanologen could forecast the outbreaks few days before.
Nevertheless one must state that despite intensive research and employment of most modern technical aids the reliable accurate forecast of a volcanic eruption is at present not yet in each case possible.
the most well-known (active) volcanos in Europe are:
- the Ätna on Sicilies;
- the Vesuv close Neapel
- the Campi Flegrei - (“burning fields”) at the other side than Vesuv with Neapel, of Europe most active volcanic zonewith numerous Fumaroli;
- the Stromboli - an island north of Sicily (Lipari islands);
- the “Santorin * " in Greece, in 17. pre-Christian century (1628 v. Chr.) by an enormous explosion destroys to a large extent - probably expired (*wirdo not know the antique volcanic name any longer, “Santorin” or “Santorini” are called today one of the three remained remaining islands from the collapsed Caldera.);
- the pico del Teide on the kanarischen Atlantic island Teneriffa is of Spain highest mountain, belonged however only political,not however geologically, to Europe.;
- the Hekla on the island Iceland controlled anyway by numerous volcanos; it breaks rather regularly every 10 years off.
- Piton of the Neiges (3,070, 50 m highly) on La Réunion, the oldest and “sleeping”Volcano (it rests for approximately 20,000 years and looks nowadays like a normal mountain!), belongs politically, but not geologically, to Europe;
- Piton de la Fournaise (2,631 m highly) on La Réunion, one of the most active volcanos of the world(and since 350,000 years!) heard politically, but not geologically, to Europe
some well-known volcanos outside of Europe are:
- of the Kilimandscharo in Africa
- of the Popocatépetl in Mexico,
- the Krakatau in Indonesia,
- the Fujisan in Japan,
- Aso san in Japan,
- the Mauna Loa on Hawaii,
- the Mauna Kea on Hawaii,
- the Mount Saint Helens in the USA,
- the Pinatubo on the Philippines,
- the Soufriere on Montserrat,
- the pico de Fogo on Fogo, cape Verde,
- the Misti in Peru,
- the Arenal in Costa Rica.
volcanos expired in Germany:
- the emperor chair close Freiburg (18 millions Years to 13 millions Years)
- in the Hegau closethe Bodensee, Baden-Wuerttemberg (14 millions Years to 7 millions Years) (z. B. the Hohentwiel)
- the Swabian volcano in Baden-Wuerttemberg (approx. 17 to 16 millions Years)
- in the volcanic Eifel in Rhineland-Palatinate/North Rhine-Westphalia (beginning before 700,000 years, last outbreak before 11.000Years)
- the bird mountain
- the kite rock in the filter mountains
- of the Otzberg and the cat embossment in the desert forest
- the Amöneburg in the Marburger country
- Limburg in Baden-Wuerttemberg
- as well as in the Rhön, in the Westerwald and in the Eifel.
Whether the German volcanos asexpired and/or. resting apply, is at present still disputed. It seems a little probably that they become again active within the next centuries, but mehren themselves the signs for size increase of the magma plume for example under the Eifel. Carbon dioxide vesicle, e.g.into the Maaren ascend, in recent time no longer than symptom lining Inge that activity are interpreted, but than indications of increasing activity. Penetrating water (groundwater, Oberflächenwasser) lends to the Eifel volcanos besides special danger, there by the enormous pressure build-up a highly explosiveMixture develops and it to Phreatomagmati explosions to come can. Already with the last outbreak before 11,000 years thereby tremendous quantities of magma, ash and cinder to the earth's surface were carried.
The highest volcano of the solar system (however already expired) is the Olympus Mons on Mars. It is with 26,4km height the highest well-known mountain of our solar system, which for a former sign volcano is extraordinarily remarkable.
Further volcanos on earth and in our solar system are to be found under list of the volcanos.
Web on the left of
|Wiktionary: Volcano - word origin, synonyms and translations|
|Commons: Volcano - pictures, videos and/or audio files|
- http://www.parautochthon.com/100584/190915.html volcanosand magma tables of rocks
- http://survival.4u.org/vulkane/index.htm volcanic monitor
- mineral Atlas: Volcano
- http://volcanoes.usgs.gov/Products/Pglossary/volcano.html (English)
- http://volcano.und.edu/ (English)
- http://www.swisseduc.ch/stromboli/ information about Stromboli, Ätna and other volcanos
- http://www.swvrc.org/cerupt.htm current eruption (English)
- volcanic side of naturgewalten.de
- world of the Eifel volcanos for pupils
- reports and pictures for the topic of volcanos
- worth knowing over volcanosand earthquake
- world of the miracles: Ticking time bomb - like volcanic eruptions to predict leave themselves