Geography: Caldera

The 3 x 4½ km summit caldera of Mount Katmai, Alaska, that formed after the 1912 VEI 6 Novarupta eruption (Wikipedia)
Etymology
noun
large, basinlike depression resulting fromthe explosion 
or collapse of the center of a volcano.

Timeframe: 1860–65

Language: Caldera comes from Spanish, it translates literally into ‘cauldron’

 Late Latin caldāria, noun use of feminine of caldārius of warming > caldarium.

Types 
  • Crater-Lake Calderas: resulting from the most explosive of eruptions described as Plinian eruptions.

“Plinian eruptions release massive amounts of lava, volcanic ash and rocks.

The Crater Lake caldera is about 10 kilometers (6 miles) wide.”

  • Shield Volcano Calderas aren’t formed by one explosion but a series of a periodic release of lava. 

“This less-explosive release of lava, known as lava fountaining, is characteristic of shield volcanoes. As a shield volcano periodically releases lava, it produces nested or terraced depressions rather than a large bowl-shaped caldera.

As a result, shield volcano calderas are usually less than 5 kilometers (3.1 miles) in diameter.”  

  • Resurgent Calderas

“Resurgent calderas are the largest volcanic structures on Earth, ranging from 15 to 100 kilometers (9 to 62 miles) in diameter. They are not associated with one particular volcano, but instead result from the widespread collapse of vast magma chambers. This caldera collapse is produced by incredibly destructive eruptions known as pyroclastic sheet flows, the likes of which have not occurred in historic times.”

A glance at the National Geographic article is a fantastic read. I’d initially chosen to research calderas to an etymological degree until I realized just how amazing these relics of earth’s violent past are and the possible futures of unsuspecting volcanoes.

It should be noted:

Calderas are inward explosions, while more circular in shape have uneven edges due to missing bits because they collapse irregularly.

Craters are outward explosions, typically smaller.

Calderas occur in space as well! Several planets including the likes of Venus and Mars, and even our moon. 

Post notes

This is my very first actual entry and I realize it appears to be an infodump. The reasoning behind the quotations is simply because I’m nowhere close to being proficient in geography and it is, after all, a learning process for me as well. I’ve never visited any calderas, unfortunately, so I can’t give any accounts and paraphrasing in this instance strikes me as fraudulent. However, this isn’t necessarily to say that all of my posts will follow this trend.

Sources (in order)
  1. Wikipedia
  2. Dictionary.com
  3. National Geographic
Disclaimer

No copyright infringement is intended, sources are cited accordingly.

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