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Volcanic Explosivity Index

From Wikipedia, the free encyclopedia

VEI and ejecta volume correlation
VEI and ejecta volume correlation

The Volcanic Explosivity Index (VEI) is a relative measure of the explosiveness of volcanic eruptions. It was devised by Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii in 1982.

Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value. The scale is open-ended with the largest volcanoes in history given magnitude 8. A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m3 (350,000 cu ft) of tephra ejected; and 8 representing a mega-colossal explosive eruption that can eject 1.0×1012 m3 (240 cubic miles) of tephra and have a cloud column height of over 20 km (66,000 ft). The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI-0, VEI-1 and VEI-2.[1]

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Transcription

This is a video by RealLifeLore, sponsored by the Great Courses Plus. We know that volcanoes can cause a massive amount of destruction whenever they erupt. They can wipe out entire cities like what happened to Pompeii in the Roman Empire or devastate entire regions like when Mount St. Helens erupted in the United States, but is it possible that if a volcano erupted with a massive enough for sometime in the future could actually destroy all of human civilization on the planet? At some point in the past, volcanoes have actually come pretty close to doing exactly that. First, we need to understand something called the Volcanic Explosivity Index, which is a scale used to measure the eruptions of volcanoes. The scale goes from zero being a relatively tiny eruption that is happening all over the world continuously all the way up to an 8, which would be a mega colossal eruption with earth-shattering consequences similar to an asteroid impact that only happens about every 50,000 years on average. For reference in regards to how powerful volcanoes can actually get both the Mount Vesuvius eruption that annihilated ancient Pompeii and the Mount St. Helens eruption 1980 would both be classified as only a level five eruption on the scale, which is incredible because the mount st. helens eruption released 24 megatons, or 1,600 times the scale of the atomic bomb dropped on Hiroshima, which means the things only gets ridiculously more powerful from here. Perhaps the best-known level 6 volcanic eruption was the Krakatoa nightmare in 1883. The volcano was located on this island in Indonesia and exploded with the on firing force of 200 Megaton 13,000 times more powerful than the Hiroshima atomic bomb and four times more powerful than even the mighty Tsar Bomba the largest nuclear weapon humanity has ever detonated this epic explosion generated the loudest sound ever known to have happened in human history shattering sailors eardrums that were located 64 kilometers from the blast and capable of being heard perfectly clear as far away as curve Australia almost the entire island of the volcano is located on was completely blown apart the blast was so powerful that it sent coral reefs that have a dormant for centuries on the ocean floor hurtling towards land as if they were asteroid and the explosion generated 30 meter high tsunamis that ravaged the rest of Indonesia everybody on the nearby island of the beefy was killed in the immediate aftermath and in total up to 120,000 people in the islands were killed in the immediate aftermath of the disaster there were reports of human skeletons on graphs that have gotten lost it he trying to escape that began washing up on the east coast of africa one entire year after the explosion but perhaps the worst part about volcanic eruptions is the massive amount of ash to get pumped into the atmosphere that can block out the sunlight and caused global temperatures to drop dramatically in the case of Krakatoa global temperatures fell by 1.2 degrees Celsius the following year and did not recover for another four years the ashen atmosphere cause weird optical effect to that made the moon occasionally appear blue or even green and even this famous painting is theorized by some to actually depict when an accurate sky above more way look like in the year following the eruption another deadly level 6 eruption happened exactly 100 years previously than this and iceland in which more sulfur dioxide was pumped into the Earth's atmosphere in just a few months than the entire industrial output of all of modern-day europe combined for three years this created a toxic gas cloud that killed fifty percent of all animal life on Iceland which caused a famine that killed twenty five percent of the human population on the island the toxic cloud then move across the sea over to the rest of Europe where 23,000 more people died in person alone from the poison gas but let's get a little more crazy and move up to what a level 7 on the scale would look like one of these such eruptions created the largest explosion ever witnessed and recorded history back only two centuries ago in 1815 also taking place on an island in Indonesia this explosion shot 400 million tons of ash into our atmosphere that plunge the entire planet into a year-long winter all life on the island where the eruption took place with annihilated a circle 600 kilometers why from the blast was shrouded in darkness for days and the year of 1816 became known as the year without a summer due to the fact that it snowed in New York and main in the middle of June and connect city got a whole 30 centimeters of snow here in the same bump this was certainly a very devastating eruption that they have immediately killed up to 100,000 people but they have also called fans were applied the future the cold temperatures that killed crops across the world about 75,000 years ago an enormous volcano may have caused humanity to come the closest that it's ever been to ultimate extinction the Toba supervolcano also located in Indonesia exploded with a level eight on our scale in these prehistoric time it was three thousand times more powerful than what happened at Mount st. Helens and ejected 100 times more ash than even a tempura explosion did in 1815 this was enough ash to completely bury all of luxembourg but he's a full kilometer of the stuff for all of Argentina beneath one meter is sent the planet into a decade-long winter more global temperatures dropped by as much as fifteen degrees celsius and early humanity was possibly almost destroyed by it the global human population they have dwindled to a few as a mere 3,000 people during those hard times which is about the same number of people that currently follow me on Facebook and Twitter but humanity managed to persevere which leaves the interesting question of what would happen if a level eight super volcano exploded today the most likely and devastating culprit would be the Yellowstone supervolcano in the United States the entire Yellowstone National Park is hiding a volcano of gargantuan proportions right beneath her visitors feet it is experienced three level eight eruptions in the past 2.1 million years with the most recent one happening 640,000 years ago there's enough magma in the volcano system underneath the surface today to fill the entire Grand Canyon 11 x over or bury the entire netherlands with one full kilometer of molten rock it is estimated that the volcano has about a one in 700,000 a chance of exploding each year which is absurdly unlikely what would happen if we were absurdly un- lucky well here's a map of what the damage would look like the states of Wyoming Idaho and Montana would be largely buried beneath a full meter of ash which would render them all uninhabitable anybody who didn't evacuate from these three states would likely be killed in the aftermath of the explosion salt lake city and Denver would also likely suffer major damage and Casualty the only part of the mainland us that would escape any ashfall would be southern Texas and southern Florida this event would likely create either the largest mass grave for the largest refugee crisis in history and the entire States where the people would have to be evacuated and probably flee east the entire western United States will be completely devastated and agricultural production in the country would be crippled it would be the biggest disaster in history and likely throw the United States into a depression multiple times words than the nineteen twenty stock market crash this in turn would throw the entire world economy into a severe depression and coupled with a 10 year long winter caused by lingering ashy atmosphere and the resulting massive crop failures and famines and the world will be a very tumultuous, cold and frightening place human civilization may be changed forever by that eruption and who knows what catastrophic change it may bring about but it likely wouldn't completely end us as a species life would go on in some way or another as it always has now after saying all of that I must take the time now so once again thank my incredible sponsor the great courses plus the great courses plus is a subscription on-demand video learning service where you can subscribe to and watch unlimited top-notch courses that are taught by brilliant ideally professors as well as experts from National Geographic the Smithsonian the culinary institute of america and hundreds of other extremely qualified individuals they offer an unlimited access to thousands of different lectures over pretty much anything that you could possibly be interested in if you enjoyed the video that you just watch then i would strongly recommend their course titled the joy of science which includes lectures on volcanic activity earthquake and plate tectonics it's a really fun subject to learn about and help out a watch with a research that I conducted for this video you can watch these or hundreds of other courses completely for free when you sign up for a 30-day free trial using the link on your screen now www.thegreatcoursesplus.com / real-life lore or you can click on the link that's in the description if you enjoyed the video that you just watch then I hope you'll subscribe to my channel by clicking here you can visit my patreon by clicking here watch them older videos of mine clicking over here on the left and i look forward to seeing you again for the next new video soon

Contents

Classification

With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much volcanic material is thrown out, to what height, and how long the eruption lasts. The scale is logarithmic from VEI-2 and up; an increase of 1 index indicates an eruption that is 10 times as powerful. As such there is a discontinuity in the definition of the VEI between indices 1 and 2. The lower border of the volume of ejecta jumps by a factor of one hundred, from 10,000 to 1,000,000 m3 (350,000 to 35,310,000 cu ft), while the factor is ten between all higher indices. In the following table, the frequency of each VEI indicates the approximate frequency of new eruptions of that VEI or higher.

VEI Ejecta
volume
(bulk)
Classification Description Plume Frequency Tropospheric
injection
Stratospheric
injection[2]
Examples
0 < 104 m3 Hawaiian Effusive < 100 m continuous negligible none
Hoodoo Mountain (c. 7050 BC),[3] Erebus (1963), Kīlauea (1977), Socorro Island (1993), Mawson Peak (2006), Dallol (2011), Piton de la Fournaise (2017)
<span style="color: black;">1</span> > 104 m3 Hawaiian / Strombolian Gentle 100 m – 1 km daily minor none
Stromboli (since Roman times), Nyiragongo (2002), Raoul Island (2006)
2 > 106 m3 Strombolian / Vulcanian Explosive 1–5 km every two weeks moderate none
Unzen (1792), Cumbre Vieja (1949), Galeras (1993), Sinabung (2010)
3 > 107 m3 Vulcanian / Peléan/Sub-Plinian Catastrophic 3–15 km 3 months substantial possible
Lassen Peak (1915), Nevado del Ruiz (1985), Soufrière Hills (1995), Ontake (2014)
4 > 0.1 km3 Peléan / Plinian/Sub-Plinian Cataclysmic > 10 km (Plinian or sub-Plinian) 18 months substantial definite
Laki (1783), Kīlauea (1790), Mayon (1814), Pelée (1902), Colima (1913), Sakurajima (1914), Katla (1918), Galunggung (1982), Eyjafjallajökull (2010), Nabro (2011), Calbuco (2015)
5 > 1 km3 Peléan/Plinian Paroxysmic > 10 km (Plinian) 12 years substantial significant
Vesuvius (79), Fuji (1707), Tarawera (1886), Agung (1963), St. Helens (1980), El Chichón (1982), Hudson (1991), Puyehue (2011)
6 > 10 km3 Plinian / Ultra-Plinian Colossal > 20 km 50–100 yrs substantial substantial
Lake Laach Volcano (c. 10,950 BC), Nevado de Toluca (8,550 BC), Veniaminof (c. 1750 BC), Lake Ilopango (450), Ceboruco (930), Huaynaputina (1600), Krakatoa (1883), Santa Maria (1902), Novarupta (1912), Pinatubo (1991)
7 > 100 km3 Ultra-Plinian Super-colossal > 20 km 500–1,000 yrs substantial substantial
Valles Caldera (1,264,000 BC), Phlegraean Fields (37,000 BC), Aira Caldera (22,000 BC), Mount Mazama (c. 5,700 BC), Kikai Caldera (4,300 BC), Cerro Blanco (c. 2300 BC), Thera (c. 1620 BC), Taupo (180), Baekdu (946), Samalas (1257), Tambora (1815)
8 > 1000 km3 Ultra-Plinian Mega-colossal > 20 km > 50,000 yrs[4][5] vast vast
La Garita (26,300,000 BC), Cerro Galán (2,200,000 BC), Huckleberry Ridge Tuff (2,100,000 BC), Yellowstone (630,000 BC), Whakamaru (in TVZ) (254,000 BC),[6] Toba (74,000 BC), Taupo (25,360 BC)

About 40 eruptions of VEI-8 magnitude within the last 132 million years (Mya) have been identified, of which 30 occurred in the past 36 million years. Considering the estimated frequency is on the order of once in 50,000 years,[4] there are likely many such eruptions in the last 132 Mya that are not yet known. Based on incomplete statistics, other authors assume that at least 60 VEI-8 eruptions have been identified.[7][8] The most recent is Lake Taupo's Oruanui eruption, more than 27,000 years ago, which means that there have not been any Holocene eruptions with a VEI of 8.[9]

There have been at least 10 eruptions of VEI-7 in the last 10,000 years. There are also 58 plinian eruptions, and 13 caldera-forming eruptions, of large, but unknown magnitudes. By 2010, the Global Volcanism Program of the Smithsonian Institution had catalogued the assignment of a VEI for 7,742 volcanic eruptions that occurred during the Holocene (the last 11,700 years) which account for about 75% of the total known eruptions during the Holocene. Of these 7,742 eruptions, about 49% have a VEI of ≤ 2, and 90% have a VEI ≤ 3.[10]

Limitations

Under the VEI, ash, lava, lava bombs, and ignimbrite are all treated alike. Density and vesicularity (gas bubbling) of the volcanic products in question is not taken into account. In contrast, the DRE (dense-rock equivalent) is sometimes calculated to give the actual amount of magma erupted. Another weakness of the VEI is that it does not take into account the power output of an eruption, which makes the VEI extremely difficult to determine with prehistoric or unobserved eruptions.

Although VEI is quite suitable for classifying the explosive magnitude of eruptions, the index is not as significant as sulphur dioxide emissions in quantifying their atmospheric and climatic impact, as a 2004 paper by Georgina Miles, Roy Grainger and Eleanor Highwood points out.

"Tephra, or fallout sediment analysis, can provide an estimate of the explosiveness of a known eruption event. It is, however, not obviously related to the amount of SO2 emitted by the eruption. The Volcanic Explosivity Index (VEI) was derived to catalogue the explosive magnitude of historical eruptions, based on the order of magnitude of erupted mass, and gives a general indication as to the height the eruptive column reached. The VEI itself is inadequate for describing the atmospheric effects of volcanic eruptions. This is clearly demonstrated by two eruptions, Agung (1963) and El Chichón (1982). Their VEI classification separates them by an order of magnitude in explosivity, although the volume of SO2 released into the stratosphere by each was measured to be broadly similar, as shown by the optical depth data for the two eruptions."[11]

Lists of large eruptions

2011 Puyehue-Cordón Caulle eruption1980 eruption of Mount St. Helens1912 eruption of NovaruptaYellowstone CalderaAD 79 Eruption of Mount Vesuvius1902 eruption of Santa María1280 eruption of Quilotoa1600 eruption of Huaynaputina2010 eruptions of EyjafjallajökullYellowstone Caldera1783 eruption of Laki1477 eruption of Bárðarbunga1650 eruption of KolumboVolcanic activity at SantoriniToba catastrophe theoryKuril IslandsBaekdu MountainKikai Caldera1991 eruption of Mount PinatuboLong Island (Papua New Guinea)1815 eruption of Mount Tambora1883 eruption of Krakatoa2010 eruptions of Mount MerapiBilly Mitchell (volcano)Taupo VolcanoTaupo VolcanoTaupo VolcanoCrater Lake
Clickable imagemap of notable volcanic eruptions. The apparent volume of each bubble is linearly proportional to the volume of tephra ejected, colour-coded by time of eruption as in the legend. Pink lines denote convergent boundaries, blue lines denote divergent boundaries and yellow spots denote hotspots.

See also

References

  1. ^ Newhall, Christopher G.; Self, Stephen (1982). "The Volcanic Explosivity Index (VEI): An Estimate of Explosive Magnitude for Historical Volcanism" (PDF). Journal of Geophysical Research. 87 (C2): 1231–1238. Bibcode:1982JGR....87.1231N. doi:10.1029/JC087iC02p01231. Archived from the original (PDF) on December 13, 2013.
  2. ^ "Volcanic Explosivity Index (VEI)". Global Volcanism Program. Smithsonian National Museum of Natural History. Archived from the original on November 10, 2011. Retrieved August 21, 2014.
  3. ^ "Global Volcanism Program - Hoodoo Mountain". volcano.si.edu.
  4. ^ a b Dosseto, A. (2011). Turner, S. P.; Van-Orman, J. A. (eds.). Timescales of Magmatic Processes: From Core to Atmosphere. Wiley-Blackwell. ISBN 978-1-4443-3260-5.
  5. ^ Rothery, David A. (2010), Volcanoes, Earthquakes and Tsunamis, Teach Yourself
  6. ^ 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. Retrieved 23 August 2010.
  7. ^ BG, Mason (2004). "The size and frequency of the largest explosive eruptions on Earth". Bull Volcanol. 66 (8): 735–748. Bibcode:2004BVol...66..735M. doi:10.1007/s00445-004-0355-9.
  8. ^ Bryan, S.E. (2010). "The largest volcanic eruptions on Earth". Earth-Science Reviews. 102 (3–4): 207–229. Bibcode:2010ESRv..102..207B. doi:10.1016/j.earscirev.2010.07.001.
  9. ^ 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.
  10. ^ Siebert, L.; Simkin, T.; Kimberly, P. (2010). Volcanoes of the World (3rd ed.). University of California Press. pp. 28–38. ISBN 978-0-520-26877-7.
  11. ^ Miles, M. G.; Grainger, R. G.; Highwood, E. J. (2004). "Volcanic Aerosols: The significance of volcanic eruption strength and frequency for climate" (PDF). Quarterly Journal of the Royal Meteorological Society. 130 (602): 2361–2376. doi:10.1256/qj.03.60.

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