Supervolcano

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World map of known VEI 7 and VEI 8 volcanoes
  VEI 8 (supervolcanoes)
  VEI 7

A supervolcano is a

eruption with a volcanic explosivity index (VEI) of 8,[1] the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers (240 cubic miles).[2]

Location of Yellowstone hotspot over time. Numbers indicate millions of years before the present.
Satellite image of Lake Toba, the site of a VEI 8 eruption c. 75,000 years ago
Cross-section through Long Valley Caldera

Supervolcanoes occur when magma in the mantle rises into the crust but is unable to break through it. Pressure builds in a large and growing magma pool until the crust is unable to contain the pressure and ruptures. This can occur at hotspots (for example, Yellowstone Caldera) or at subduction zones (for example, Toba).[3][4]

Large-volume supervolcanic eruptions are also often associated with large igneous provinces, which can cover huge areas with lava and volcanic ash. These can cause long-lasting climate change (such as the triggering of a small ice age) and threaten species with extinction. The Oruanui eruption of New Zealand's Taupō Volcano (about 26,500 years ago) was the world's most recent VEI-8 eruption.[5]

Terminology

The term "supervolcano" was first used in a volcanic context in 1949.

peaks in the Three Sisters area were remnants of Mount Multnomah after it had been largely destroyed by violent volcanic explosions, similarly to Mount Mazama.[7] In his 1948 book The Ancient Volcanoes of Oregon, volcanologist Howel Williams ignored the possible existence of Mount Multnomah, but in 1949 another volcanologist, F. M. Byers Jr., reviewed the book, and in the review, Byers refers to Mount Multnomah as a "supervolcano".[6][8][9]

More than fifty years after Byers' review was published, the term supervolcano was popularised by the

Horizon in 2000, referring to eruptions that produce extremely large amounts of ejecta.[10][11]

The term megacaldera is sometimes used for caldera supervolcanoes, such as the Blake River Megacaldera Complex in the Abitibi greenstone belt of Ontario and Quebec, Canada.[12]

Though there is no well-defined minimum explosive size for a "supervolcano", there are at least two types of volcanic eruptions that have been identified as supervolcanoes: large igneous provinces and massive eruptions.[13]

Large igneous provinces

Map of large flood basalt igneous provinces worldwide

Large igneous provinces, such as Iceland, the Siberian Traps, Deccan Traps, and the Ontong Java Plateau, are extensive regions of basalts on a continental scale resulting from flood basalt eruptions. When created, these regions often occupy several thousand square kilometres and have volumes on the order of millions of cubic kilometers. In most cases, the lavas are normally laid down over several million years. They release large amounts of gases.

The Réunion hotspot produced the Deccan Traps about 66 million years ago, coincident with the Cretaceous–Paleogene extinction event. The scientific consensus is that an asteroid impact was the cause of the extinction event, but the volcanic activity may have caused environmental stresses on extant species up to the Cretaceous–Paleogene boundary.[14] Additionally, the largest flood basalt event (the Siberian Traps) occurred around 250 million years ago and was coincident with the largest mass extinction in history, the Permian–Triassic extinction event, although it is unknown whether it was solely responsible for the extinction event.

Such outpourings are not explosive, though

Laki fissure
, which is approximately 40 km (25 mi) long. An estimated 14 km3 (3.4 cu mi) of basaltic lava was poured out during the eruption (VEI 4).

The Ontong Java Plateau has an area of about 2,000,000 km2 (770,000 sq mi), and the province was at least 50% larger before the Manihiki and Hikurangi Plateaus broke away.

Massive explosive eruptions

Volcanic eruptions are classified using the volcanic explosivity index. It is a logarithmic scale, and an increase of one in VEI number is equivalent to a tenfold increase in volume of erupted material. VEI 7 or VEI 8 eruptions are so powerful that they often form circular calderas rather than cones because the downward withdrawal of magma causes the overlying rock mass to collapse into the empty magma chamber beneath it.

Known super eruptions

Based on incomplete statistics, at least 60 VEI 8 eruptions have been identified.[13][15]

Well-known VEI 8 eruptions
Name Zone Location Notes Years ago (approx.) Ejecta bulk volume (approx.) Reference
Youngest Toba eruption Toba Caldera, North Sumatra Sumatra, Indonesia Produced 439–631 million tons of sulfuric acid 75,000 2,000–13,200 km3 [16][17][18][19][20][21][22]
Flat Landing Brook Formation Tetagouche Group New Brunswick, Canada Possibly the largest known supereruption. Existence as a single eruption is controversial, and it could have been a multiple 2,000+ km³ event that spanned less than a million years 466,000,000 2,000–12,000 km3 [23][24]
Wah Wah Springs Caldera Indian Peak–Caliente Caldera Complex Utah, United States The largest of the Indian Peak-Caliente Caldera Complex eruptions, preserved as the Wah Wah Springs Tuff; includes pyroclastic flows more than 500 meters (1,600 ft) thick 30,600,000 5,500–5,900 km3 [25][26]
La Garita Caldera San Juan volcanic field Colorado, United States Fish Canyon eruption 27,800,000 5,000 km3 [27][28]
Grey's Landing Supereruption Yellowstone hotspot United States Deposited the Grey's Landing Ignimbrite 8,720,000 2,800 km3 [29]
La Pacana Andes Central Volcanic Zone Chile Responsible for the Antana Ignimbrite 4,000,000 2,500 km3 [30]
Huckleberry Ridge eruption Yellowstone hotspot Idaho, United States Huckleberry Ridge Tuff; consisted of three distinct eruptions separated by years to decades 2,100,000 2,450–2,500 km3 [31][32]
Whakamaru Caldera Taupō Volcanic Zone North Island, New Zealand Whakamaru Ignimbrite/Mount Curl Tephra 340,000 2,000 km3 [33]
Heise Volcanic Field Yellowstone hotspot Idaho, United States Kilgore Tuff 4,500,000 1,800 km3 [34]
McMullen Supereruption Yellowstone hotspot Southern Idaho, United States McMullen Ignimbrite 8,990,000 1,700 km3 [29]
Heise Volcanic Field Yellowstone hotspot Idaho, United States Blacktail Tuff 6,000,000 1,500 km3 [34]
Cerro Guacha Altiplano–Puna volcanic complex Sur Lípez, Bolivia Guacha ignimbrite, two smaller eruptions identified 5,700,000 1,300 km3 [35]
Mangakino Caldera Taupō Volcanic Zone North Island, New Zealand Kidnappers eruption 1,080,000 1,200 km3 [36]
Oruanui eruption Taupō Volcanic Zone North Island, New Zealand Taupō Volcano (Lake Taupō) 26,500 1,170 km3 [37]
Galán Andes Central Volcanic Zone Catamarca, Argentina Consisted of three distinct eruptions, separated by 30-40 thousand years 2,500,000 1,050 km3 [38]
Lava Creek eruption Yellowstone hotspot Idaho, Montana, and Wyoming, United States Lava Creek Tuff; consisted of two distinct eruptions separated by years 640,000 1,000 km3 [31][32][26]

Media portrayal

  • Nova featured an episode "Mystery of the Megavolcano" in September 2006 examining such eruptions in the last 100,000 years.[39]
  • Supervolcano is the title of a British-Canadian television disaster film, first released in 2005. It tells a fictional story of a supereruption at Yellowstone.
  • In the 2009 disaster film 2012, a supereruption of Yellowstone is one of the events that contributes to a global cataclysm.

Gallery

  • Volcano, lake, and caldera locations in the Taupō Volcanic Zone
    Volcano, lake, and caldera locations in the Taupō Volcanic Zone

See also

Notes

  1. ^ The term was first used in Conquering the World, a 1925 travelogue by Helen Bridgeman, referring to an Indian Ocean sunset in Indonesia as an upside down "super-volcano".[6]
  2. ^ Subsequent research proved that each peak of the Three Sisters was formed independently, and that Mount Multnomah never existed.[citation needed]

References

  1. .
  2. USGS Yellowstone Volcano Observatory. 21 August 2015. Archived
    from the original on 3 July 2017. Retrieved 22 August 2017.
  3. .
  4. .
  5. .
  6. ^ a b c Klemetti, Erik (4 October 2013). "The rise of a supervolcano". Wired. Retrieved 29 November 2023.
  7. ^ Harris, Stephen (1988). Fire Mountains of the West: The Cascade and Mono Lake Volcanoes. Missoula, Mountain Press.
  8. ^ supervolcano, n. Oxford English Dictionary, third edition, online version June 2012. Retrieved on 2012-08-17.
  9. ^ Byers Jr., F. M. (May 1949). "Review of The Ancient Volcanoes of Oregon, by H. Williams". The Journal of Geology. 57 (3): 325 – via JSTOR.
  10. ^ "Supervolcanoes". bbc.co.uk. BBC. 3 February 2000. Retrieved 30 November 2023.
  11. ^ USGS Cascades Volcano Observatory Archived 4 February 2012 at the Wayback Machine. Vulcan.wr.usgs.gov. Retrieved on 2011-11-18.
  12. .
  13. ^ .
  14. .
  15. .
  16. .
  17. doi:10.1029/JB091iB10p10355.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  18. S2CID 128626019.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  19. (PDF) from the original on 17 June 2010.
  20. .
  21. .
  22. .
  23. ^ "Lexique du substrat rocheux". dnr-mrn.gnb.ca. Retrieved 22 December 2019.
  24. ^ "A mid-Darriwilian super volcano in northern New Brunswick, rapid climate change and the start of the great Ordovician biodiversification event" (PDF). pp. 118–119. Archived (PDF) from the original on 12 December 2019. Retrieved 11 November 2023.
  25. .
  26. ^ a b King, Hobart M. "Volcanic Explosivity Index: Measuring the size of an eruption". Geology.com.
  27. ^ Ort, Michael (22 September 1997). "La Garita Caldera". Northern Arizona University. Archived from the original on 19 May 2011. Retrieved 5 August 2010.
  28. ^ Lipman, Peter W. (2 November 2007). "Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado". USGS Investigations Series I-2799. Archived from the original on 31 August 2010. Retrieved 6 August 2010. {{cite journal}}: Cite journal requires |journal= (help)
  29. ^ . Retrieved 21 June 2022.
  30. .
  31. ^ a b Large Holocene Eruptions. Global Volcanism Program. Archived 13 February 2010 at the Wayback Machine. Volcano.si.edu. Retrieved on 2011-11-18.
  32. ^ a b "What is a supervolcano? What is a supereruption?". USGS.
  33. S2CID 4332421
    . The minimum total volume of tephra is 1,200 km3 but probably nearer 2,000 km3, ...
  34. ^ .
  35. .
  36. ^ Rejuvenation and Repeated Eruption of a 1.0 Ma Supervolcanic System at Mangakino Caldera, Taupo Volcanic Zone, New Zealand American Geophysical Union, Fall Meeting 2012, abstract #V31C-2797. Retrieved 10 September 2017.
  37. ISSN 0377-0273
    .
  38. .
  39. ^ "Mystery of the Megavolcano" Archived 17 June 2017 at the Wayback Machine. Pbs.org. Accessed on 2017-10-12.

Further reading

External links