Calderas and 'Super-Eruptions'

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In summary, Gualda and Sutton found that the onset of decompression, which releases the gas bubbles that power an eruption, starts less than a year before eruption. This information could help predict when another super-eruption will strike the Earth.
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Astronuc
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Super-eruptions may give only a year’s warning before they blow
http://news.vanderbilt.edu/2016/07/super-eruptions-may-give-only-a-years-warning-before-they-blow/
“The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales,” said Gualda. Tens of thousands of years are needed to prime the crust to generate sufficient eruptible magma. Once established, these melt-rich, giant magma bodies are unstable features that last for only centuries to few millennia. “Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption.”

In a paper entitled “The year leading to a supereruption” by Guilherme Gualda, associate professor of Earth and environment sciences at Vanderbilt University, and Stephen Sutton at the University of Chicago published July 20 in the journal PLOS One, the scientists report the results of a new microscopic analysis of quartz crystals in pumice taken from the Bishop Tuff in eastern California, which is the site of the super-eruption that formed the Long Valley Caldera 760,000 years ago.

Very large eruptions – including super-eruptions – have taken place in a number of places worldwide in the recent geological past. The Taupo Volcanic Zone in New Zealand was the site of the most recent super-eruption – the Oruanui eruption at 26,500 years – and it includes deposits from more than a dozen very large eruptions that took place in the last couple of million years. Campi Flegrei in Italy produced a very large eruption 40,000 years ago. Indonesia was the site of the Toba super-eruption in Sumatra 75,000 years ago and the Tambora eruption in 1815. In the United States, Yellowstone has experienced three super-eruptions over the last two million years. In light of this evidence, it seems inevitable that another super-eruption will strike the Earth in the future.
Since pumice is formed from super-heated, highly pressurized rock that is violently ejected from a volcano, I assume it is produced in super-eruptions, since they are super-sized because of the gas in the magma.

https://en.wikipedia.org/wiki/Phlegraean_Fields (Campi Flegrei)
https://en.wikipedia.org/wiki/Taupo_Volcano
https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora
https://en.wikipedia.org/wiki/Toba_catastrophe_theory

It would be interesting to review the compositions of the cited super-eruptions.
 
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Instead of "giant asteroid 2016", we might get "giant volcano 2017"?
Let's hope it will stay without a major eruption for a while.
 
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Is it like earthquakes? The longer you wait the bigger the bang?
 
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Not necessarily, but as far as I know that is the general trend. A few hundred years won't make a notable difference to the intensity, however, but a large difference to the question who will see the explosion.
 
  • #6
Campi Flegrei is in the news seven (7) years later, because of increased seismic activity and venting.

https://www.nationalgeographic.com/...naples-italy-convulsing-campi-flegrei-caldera (may require subscription)

https://www.volcanodiscovery.com/campi-flegrei/news.html

https://www.reuters.com/world/europ...italian-town-supervolcano-rumbles-2023-10-27/
POZZUOLI, Italy, Oct 27 (Reuters) - The talk in shops and coffee bars in Pozzuoli, a port town outside Naples, is not about soccer or politics, but of the fear that has gripped residents since a supervolcano sparked a swarm of earthquakes.

Over the past weeks the government has been planning for a possible mass evacuation of tens of thousands of people who live around the vast volcanic area known as the Campi Flegrei, or Phlegraean Fields,

Just in time for whatever comes next - Principal component analysis on twenty years (2000–2020) of geochemical and geophysical observations at Campi Flegrei active caldera
https://www.nature.com/articles/s41598-023-45108-0
 

1. What is a caldera?

A caldera is a large, basin-shaped volcanic depression that forms when a magma chamber beneath a volcano partially or completely empties, causing the overlying rock to collapse.

2. How are calderas different from regular volcanic craters?

Calderas are much larger in size and have a more circular or elliptical shape compared to regular volcanic craters. They are also formed by different mechanisms, with calderas being the result of collapse rather than volcanic explosions.

3. What is a 'super-eruption'?

A 'super-eruption' is an eruption that is classified as a VEI 8 (Volcanic Explosivity Index) event, meaning it has a magnitude of 8 or higher on a scale of 0-8. These eruptions are extremely rare and release enormous amounts of volcanic material and ash into the atmosphere.

4. How do caldera-forming eruptions differ from regular volcanic eruptions?

Caldera-forming eruptions are much larger and more explosive than regular volcanic eruptions. They involve the rapid emptying of a large magma chamber, causing the overlying rock to collapse and form a caldera. In contrast, regular volcanic eruptions are typically smaller and involve the eruption of magma through a vent or fissure on the surface.

5. What are the potential hazards associated with super-eruptions and calderas?

Super-eruptions and calderas can have a wide range of hazards and impacts, including pyroclastic flows, lahars, ash fall, and volcanic gases. These events can also have significant societal and economic impacts, such as disruptions to air travel, damage to infrastructure, and loss of agriculture and livestock in affected areas.

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