Caldera (crater)

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Caldera (9.5 km diameter and 600 m depth) of the Mount Aniakchak volcano in Alaska with a smaller volcanic cone formed in it
Pico do Fogo ( Fogo ): semicircular caldera with almost vertical walls
Teide ( Tenerife ) and the caldera, view from Guajara
Caldera of the Pinatubo volcano with crater lake
Caldera of Santorini
False-color satellite image of Lake Toba , the 100 km long and 30 km wide caldera of a super volcano
Lagoa Azul and Lagoa Verde on Sao Miguel (Azores)
Image of the Sakura Jima . The volcano lies within the bay that was formed by the Aira caldera.
Ice-filled caldera of the Katla volcano under the ice cap of the Mýrdalsjökull glacier shield in southern Iceland

A caldera ( Spanish caldera , German 'boiler' , Portuguese Caldeira ) is a boiler- shaped structure of volcanic origin.

The following are to be distinguished:

Emergence

Calderas are created either by explosive eruptions ( funnels ) or by the collapse of near-surface magma chambers of a central volcano that have previously been emptied by eruptions . Explosion caldera and collapse caldera are often difficult to distinguish from one another, especially since the floor of a young caldera is often covered by flowing lava . After the lava cools, low-lying calderas often fill with water and then form a caldera lake .

Caldera of super volcanoes can take on enormous proportions, the caldera of the first Yellowstone volcanic eruption was 80 kilometers long and 55 kilometers wide.

If the volcano is still active, volcanic cones can form again on the floor of a caldera, as happened, for example, with Vesuvius or the Aira caldera . This formation of a volcano on an old volcano is known as the Somma volcano . The individual stages of formation are designated as follows: primordial comma - old comma - young comma - Vesuvius stage (renewed eruption).

Calderas in calderas are also observed, such as the Halemaʻumaʻu caldera at the bottom of the Kīlauea caldera.

  • 1. Eruption from a (side) crater

  • 2. The floor sinks through the collapsing magma chamber

  • 3. Ash and debris deposits on the ground; Penetrating groundwater can lead to geysers

  • 4. The cooled caldera fills with a caldera lake

Formation of a caldera, e.g. Mount Mazama, Crater Lake

Well-known calderas

Among the most important calderas of the include Teide (Tenerife), the Lake Toba (Sumatra), the Yellowstone -Caldera (USA) and the caldera of the archipelago of Santorini .

The Caldera de Taburiente (La Palma), which originally gave its name, is probably not a caldera from a geological point of view, but rather was created by later erosion.

Alien calderas

Olympus Mons on Mars

On various celestial bodies of the solar system that have a past or recent volcanism, caldera structures were discovered on images obtained by space probes, some of which are significantly larger than terrestrial calderas. Hundreds of calderas with a diameter of up to 400 km have been discovered on Jupiter's volcanically active moon Io .

See also

Web links

Commons : Caldera (crater)  - album with pictures, videos and audio files
Wiktionary: Caldera  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Frank Ahnert: Introduction to Geomorphology , 1996, 2009, ISBN 978-3-8252-8103-8 , p. 280