What is Caldera?

Caldera is huge basin shapped semicircular depression, calderas, like crater lake in Oregon USA, are often many kilimeters in diameter, produced when deep magma chambers inder a volacno empty out (during an eruption) and the overlying land collapses inward producing a topographic depression. Yellowstone Valley occupies one of the largest calderas in USA. Many geysers, hot springs, fumarol in the valley are related to groundwater circulating to depth being heated by shallow magma and mixing with volcanic gases that escape through minor cracks in the crust of the earth.

Caldera may be relatively stable for tens or hundreds of thousand of years but often magma reeters the collapsed magma chamber and causes it to rise up or inflate. This forms a resurgent caldera which can produce a catastrophic volcano eruption.

Yellowstone Caldera

Yellowstone Profile

http://www.nps.gov/yell/naturescience/images/hotspot_yell2_1.gif

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Sumber https://geograph88.blogspot.com/

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