Calderas


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Calderas

 

large oval-shaped or round depressions of volcanic origin, with steep sides that are frequently stepped. Calderas are up to 10-20 km across and several hundred meters deep. A distinction is made between explosion calderas, which are formed during powerful explosions of gases escaping from volcanic vents, and collapse calderas, which occur when the roof of an underground volcanic focus sinks along circular fractures because material has been discharged from the focus during volcanic eruptions. Collapse calderas are more common and larger than explosion calderas.

References in periodicals archive ?
The new approach was applied in southern Italy to the Campi Flegrei, a caldera close to Naples, which has a population of nearly one million.
"One question that has puzzled scientists is where magma is located beneath the caldera, and our study provides the first evidence of a hot zone under the city of Pozzuoli that extends into the sea at a depth of [2.5 miles]," lead researcher Luca De Siena said in a statement from the (https://www.abdn.ac.uk/news/11141/) University of Aberdeen .
And when the day was especially clear, I also saw glimpses of the Batangas side of the Taal Caldera.
The massif has geologic and morphologic characteristics widely different from the above-mentioned volcanic calderas. The main constituent rocks are holocrystalline aegirine phonolite, so-called tinguaite, nepheline syenite, and vent-filling intrusive pyroclastic rocks.
(1984) Formation of the Aira Caldera, southern Kyushu, ~22,000 years ago.
Calderas, which typically exhibit high levels of seismic and hydrothermal activity, often swell, suggesting movement of fluids beneath the surface.
UMISA (based in Barcelona, Spain) has a technical assistance and sales agreement with Cuba's Asociacion Nacional de Calderas (National Boiler Association, Alastor) to modernize the production of industrial boilers and to improve the quality of industrial boilers manufactured by the 18-division Alastor.