Volcanic explosivity index

Thevolcanic explosivity index(VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised byChristopher G. Newhallof theUnited States Geological SurveyandStephen Selfin 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 eruptions in history given a magnitude of 8. A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m³(350,000 cu ft) oftephraejected; and 8 representing asupervolcanic eruptionthat can eject1.0×10¹²m³(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]

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	Periodicity	Tropospheric injection	Stratospheric injection^[2]
VEI	Ejecta volume (bulk)	Examples
0	< 10⁴m³	Hawaiian	Effusive	< 100 m	constant	negligible	none
0	< 10⁴m³	Kīlauea(current),Mawson Peak(current),Dallol(2011),Holuhraun(2014-2015),Fagradalsfjall(2021-2023),Mauna Loa(1975,1984,2022)
1	> 10⁴m³	Hawaiian /Strombolian	Gentle	100 m – 1 km	daily	minor	none
1	> 10⁴m³	Yakedake(1995),Raoul Island(2006),Havre Seamount(2012),Dieng Volcanic Complex(1964, 1979, 2017),Nyiragongo(1977, 2002,2021)
2	> 10⁶m³	Strombolian /Vulcanian	Explosive	1–5 km	2 weeks	moderate	none
2	> 10⁶m³	Stromboli(since 1934),Etna(current),Unzen(1792),Ritter Island(1888),Galeras(1993),Whakaari / White Island(2019),Marapi(2023)
3	> 10⁷m³	Strombolian / Vulcanian /Peléan/ Sub-Plinian	Severe	3–15 km	3 months	substantial	possible
3	> 10⁷m³	Surtsey(1963-1967),Nevado del Ruiz(1985),Redoubt(1989-1990),Soufrière Hills(1997),Ontake(2014),Fuego(2018),Cumbre Vieja(2021)
4	> 0.1 km³	Peléan /Plinian/ Sub-Plinian	Catastrophic	> 10 km	18 months	substantial	definite
4	> 0.1 km³	Laki(1783),Bandai(1888),Pelée(1902),Lamington(1951),Eyjafjallajökull(2010),Merapi(2010),Taal(2020),Semeru(2021)
5	> 1 km³	Peléan / Plinian	Cataclysmic	> 10 km	12 years	substantial	significant
5	> 1 km³	Vesuvius(79),Fuji(1707),Tarawera(1886),St. Helens(1980),El Chichón(1982),Puyehue(2011),Hunga Tonga–Hunga Haʻapai(2022)
6	> 10 km³	Plinian /Ultra-Plinian	Colossal	> 20 km	50–100 years	substantial	substantial
6	> 10 km³	Lake Ilopango(450),Huaynaputina(1600),Krakatoa(1883),Santa Maria(1902),Novarupta(1912),Pinatubo(1991),^[3]
7	> 100 km³	Ultra-Plinian	Super-colossal	> 20 km	500–1,000 years	substantial	substantial
7	> 100 km³	Long Valley(760 kyr),Campi Flegrei(37 kyr),Aira(22 kyr),Mazama(5700 BC),Kikai(4300 BC),Samalas(1257),Tambora(1815),Santorini(1610 BC)
8	> 1,000 km³	Ultra-Plinian	Mega-colossal	> 20 km	> 50,000 years^[4]^[5]	vast	vast
8	> 1,000 km³	Flat Landing Brook(Ordovician),Wah Wah Springs(30 Mya),La Garita(26.3 Mya),Yellowstone(2.1 Mya,640 kyr),Toba(74 kyr),Taupō(26.5 kyr)

About 40 eruptionsof 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.^[6]^[7]The most recent isLake Taupō'sOruanui eruption,more than 27,000 years ago, which means that there have not been anyHoloceneeruptions with a VEI of 8.^[6]

There have been at least10 eruptions of VEI-7in the last 11,700 years. There are also 58 Plinian eruptions, and 13 caldera-forming eruptions, of large, but unknown magnitudes. By 2010, theGlobal Volcanism Programof theSmithsonian Institutionhad cataloged the assignment of a VEI for 7,742 volcanic eruptions that occurred during theHolocene(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 or lower, and 90% have a VEI of 3 or lower.^[8]

Limitations

Under the VEI,ash,lava,lava bombs,andignimbriteare all treated alike.Densityandvesicularity(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 ofmagmaerupted. 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 assulfur dioxideemissions in quantifying their atmospheric and climatic impact.^[9]

Lists of notable eruptions

Clickable imagemap of notablevolcanic eruptions.The apparent volume of each bubble is linearlyproportionalto thevolume of tephraejected, colour-coded by time of eruption as in the legend. Pink lines denoteconvergent boundaries,blue lines denotedivergent boundariesand yellow spots denotehotspots.

Timeline of volcanism on Earth(mostly VEI-6, within 2 kya)
List of volcanic eruptions 1500–1999
List of volcanic eruptions in the 21st century
List of volcanic eruptions by death toll
List of large Holocene volcanic eruptions(VEI-5–7)
List of large volcanic eruptions(VEI-5–8, within 450+ Mya)
List of largest volcanic eruptions(VEI-7–8, mostly within 500 Mya)

References

^ 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 fromthe original(PDF)on December 13, 2013.
^ "Volcanic Explosivity Index (VEI)".Global Volcanism Program.Smithsonian National Museum of Natural History.Archived fromthe originalon November 10, 2011.RetrievedAugust 21,2014.
^Karstens, Jens; Preine, Jonas; Crutchley, Gareth J.; Kutterolf, Steffen; van der Bilt, Willem G. M.; Hooft, Emilie E. E.; Druitt, Timothy H.; Schmid, Florian; Cederstrøm, Jan Magne; Hübscher, Christian; Nomikou, Paraskevi; Carey, Steven; Kühn, Michel; Elger, Judith; Berndt, Christian (2023-04-29)."Revised Minoan eruption volume as benchmark for large volcanic eruptions".Nature Communications.14(1): 2497.doi:10.1038/s41467-023-38176-3.ISSN 2041-1723.PMC10148807.PMID 37120623.
^^a ^bDosseto, 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.
^Rothery, David A. (2010),Volcanoes, Earthquakes and Tsunamis,Teach Yourself
^^a ^b 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.S2CID 129680497.
^Bryan, S.E. (2010)."The largest volcanic eruptions on Earth"(PDF).Earth-Science Reviews.102(3–4): 207–229.Bibcode:2010ESRv..102..207B.doi:10.1016/j.earscirev.2010.07.001.
^ 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.
^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.Bibcode:2004QJRMS.130.2361M.doi:10.1256/qj.03.60.S2CID 53005926.

External links

VEI glossary entryfrom aUSGSwebsite
How to measure the size of a volcanic eruption,fromThe Guardian
The size and frequency of the largest explosive eruptions on Earth,a 2004 article from theBulletin of Volcanology
List of Large Holocene Eruptions (VEI > 4) from the Smithsonian Global Volcanism Program Archived2012-01-17 at theWayback Machine

[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 fromthe original(PDF)on December 13, 2013.

[2] "Volcanic Explosivity Index (VEI)".Global Volcanism Program.Smithsonian National Museum of Natural History.Archived fromthe originalon November 10, 2011.RetrievedAugust 21,2014.

[3] Karstens, Jens; Preine, Jonas; Crutchley, Gareth J.; Kutterolf, Steffen; van der Bilt, Willem G. M.; Hooft, Emilie E. E.; Druitt, Timothy H.; Schmid, Florian; Cederstrøm, Jan Magne; Hübscher, Christian; Nomikou, Paraskevi; Carey, Steven; Kühn, Michel; Elger, Judith; Berndt, Christian (2023-04-29)."Revised Minoan eruption volume as benchmark for large volcanic eruptions".Nature Communications.14(1): 2497.doi:10.1038/s41467-023-38176-3.ISSN 2041-1723.PMC10148807.PMID 37120623.

[Dosseto-4] 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.

[Rothery2010-5] Rothery, David A. (2010),Volcanoes, Earthquakes and Tsunamis,Teach Yourself

[Mason2004-6] 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.S2CID 129680497.

[7] Bryan, S.E. (2010)."The largest volcanic eruptions on Earth"(PDF).Earth-Science Reviews.102(3–4): 207–229.Bibcode:2010ESRv..102..207B.doi:10.1016/j.earscirev.2010.07.001.

[8] 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.

[JRMS-9] 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.Bibcode:2004QJRMS.130.2361M.doi:10.1256/qj.03.60.S2CID 53005926.

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