A supervolcano is a volcano that has had an eruption with a Volcanic Explosivity Index (VEI) of 8, 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).[1]
Volcano that has erupted 1000 cubic km of lava in a single eruption
For other uses, see Supervolcano (disambiguation).
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).[2][3]
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.[4]
Terminology
The term "supervolcano" was first used in a volcanic context in 1949.[note 1]
Its origins lie in an early 20th-century scientific debate about the geological history and features of the Three Sisters volcanic region of Oregon in the United States. In 1925, Edwin T. Hodge suggested that a very large volcano, which he named Mount Multnomah, had existed in that region.[note 2] He believed that several 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.[6] 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.,[7] reviewed the book, and in the review, Byers refers to Mount Multnomah as a supervolcano.[8]
More than fifty years after Byers' review was published, the term supervolcano was popularised by the BBC popular science television program Horizon in 2000, referring to eruptions that produce extremely large amounts of ejecta.[9][10]
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.[citation needed]
Eruptions that rate VEI8 are termed "super eruptions".[11] 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.[12]
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 66million years ago, coincident with the Cretaceous–Paleogene extinction event. The scientific consensus is that a meteor 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.[13] Additionally, the largest flood basalt event (the Siberian Traps) occurred around 250million 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 lava fountains may occur. Many volcanologists consider Iceland to be a large igneous province that is currently being formed. The last major outpouring occurred in 1783–84 from the Laki fissure, which is approximately 40km (25mi) long. An estimated 14km3 (3.4cumi) of basaltic lava was poured out during the eruption (VEI 4).
The Ontong Java Plateau has an area of about 2,000,000km2 (770,000sqmi), and the province was at least 50% larger before the Manihiki and Hikurangi Plateaus broke away.
Massive explosive eruptions
See also: List of largest volcanic eruptions
Volcanic eruptions are classified using the Volcanic explosivity index, or VEI. It is a logarithmic scale, which means that 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.[12][14] Below is a list of well-known super-eruptions.
VEI 8 eruptions have happened in the following locations.
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.
The largest of the Indian Peak-Caliente Caldera Complex eruptions, preserved as the Wah Wah Springs Tuff; includes pyroclastic flows more than 4,000 meters (13,000ft) thick.
Nova featured an episode "Mystery of the Megavolcano" in September 2006 examining such eruptions in the last 100,000 years.[37]
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.
Gallery
Volcano, lake, and caldera locations in the Taupō Volcanic Zone
See also
Volcanoes portal
Global catastrophic risk– Potentially harmful worldwide events
Toba catastrophe theory– Supereruption 75,000 years ago that may have caused a global volcanic winter
Volcanic winter– Temperature anomaly event caused by a volcanic eruption
Notes
The term entered the English language already in a 1925 book, Conquering the World by Helen Bridgeman, about Indonesia to refer to an Indian Ocean sunset.[5]
Subsequent research proved that each peak of the Three Sisters was formed independently, and that Mount Multnomah never existed.[citation needed]
References
"Questions About Supervolcanoes". Volcanic Hazards Program. USGS Yellowstone Volcano Observatory. 21 August 2015. Archived from the original on 3 July 2017. Retrieved 22 August 2017.
Wilson, C. J. N. (2001). "The 26.5ka Oruanui eruption, New Zealand: An introduction and overview". Journal of Volcanology and Geothermal Research. 112 (1–4): 133–174. Bibcode:2001JVGR..112..133W. doi:10.1016/S0377-0273(01)00239-6.
[when?]
Harris, Stephen (1988) Fire Mountains of the West: The Cascade and Mono Lake Volcanoes, Missoula, Mountain Press.
Keller, G (2014). "Deccan volcanism, the Chicxulub impact, and the end-Cretaceous mass extinction: Coincidence? Cause and effect?". Geological Society of America Special Papers. 505: 57–89. doi:10.1130/2014.2505(03). ISBN9780813725055.
Knight, M.D., Walker, G.P.L., Ellwood, B.B., and Diehl, J.F. (1986). "Stratigraphy, paleomagnetism, and magnetic fabric of the Toba Tuffs: Constraints on their sources and eruptive styles". Journal of Geophysical Research. 91 (B10): 10355–10382. Bibcode:1986JGR....9110355K. doi:10.1029/JB091iB10p10355.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Ninkovich, D., Sparks, R.S.J., and Ledbetter, M.T. (1978). "The exceptional magnitude and intensity of the Toba eruption, Sumatra: An example of using deep-sea tephra layers as a geological tool". Bulletin Volcanologique. 41 (3): 286–298. Bibcode:1978BVol...41..286N. doi:10.1007/BF02597228. S2CID128626019.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Williams, M.A.J. & Royce, K. (1982). "Quaternary geology of the middle son valley, North Central India: Implications for prehistoric archaeology". Palaeogeography, Palaeoclimatology, Palaeoecology. 38 (3–4): 139. Bibcode:1982PPP....38..139W. doi:10.1016/0031-0182(82)90001-3.
"Archived copy"(PDF). Archived from the original(PDF) on 12 December 2019. Retrieved 11 September 2019.{{cite web}}: CS1 maint: archived copy as title (link)
Ort, Michael (22 September 1997). "La Garita Caldera". Northern Arizona University. Archived from the original on 19 May 2011. Retrieved 5 August 2010.
Froggatt, P. C.; Nelson, C. S.; Carter, L.; Griggs, G.; Black, K. P. (13 February 1986). "An exceptionally large late Quaternary eruption from New Zealand". Nature. 319 (6054): 578–582. Bibcode:1986Natur.319..578F. doi:10.1038/319578a0. S2CID4332421. The minimum total volume of tephra is 1,200 km3 but probably nearer 2,000 km3, ...
Lisa A. Morgan & William C. McIntosh (2005). "Timing and development of the Heise volcanic field, Snake River Plain, Idaho, western USA". GSA Bulletin. 117 (3–4): 288–306. Bibcode:2005GSAB..117..288M. doi:10.1130/B25519.1. S2CID53648675.
Salisbury, M. J.; Jicha, B. R.; de Silva, S. L.; Singer, B. S.; Jimenez, N. C.; Ort, M. H. (21 December 2010). "40Ar/39Ar chronostratigraphy of Altiplano-Puna volcanic complex ignimbrites reveals the development of a major magmatic province". Geological Society of America Bulletin. 123 (5–6): 821–840. Bibcode:2011GSAB..123..821S. doi:10.1130/B30280.1.
Mason, Ben G.; Pyle, David M.; Oppenheimer, Clive (2004). "The size and frequency of the largest explosive eruptions on Earth". Bulletin of Volcanology. 66 (8): 735–748. Bibcode:2004BVol...66..735M. doi:10.1007/s00445-004-0355-9. S2CID129680497.
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