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VEI and ejecta volume correlation


The Volcanic Explosivity Index (VEI) was devised by Chris Newhall of the U.S. Geological Survey and Steve Self at the University of Hawai imarker in 1982 to provide a relative measure of the explosiveness of volcanic eruptions.

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 (less than 104 cubic metres of tephra ejected) with 8 representing a mega-colossal explosive eruption that can eject 1012 cubic metres of tephra and have a cloud column height of over . Each interval on the scale represents a tenfold increase in observed eruption criteria.

Note that ash, volcanic bombs, and ignimbrite are all treated alike — this is due to taking into account the vesicularity (gas bubbling) of the volcanic products in question and the DRE (Dense-Rock Equivalent) is calculated to give the actual amount of magma erupted. One weakness of the VEI is that it does not take into account the magnitude of power output of an eruption. This, of course, is extremely difficult to detect with prehistoric or unobserved eruptions.

Classification

Scientists indicate how powerful volcanic eruptions are using the VEI. The VEI stands for Volcanic Explosivity Index. It records how much volcanic material is thrown out, how high the eruption goes, and how long it lasts. The scale goes from 0 to 8. An increase of 1 indicates a 10 times more powerful eruption.

Note: 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 100 from 10,000 to 1,000,000 m³ while the factor is 10 between all higher indices.

VEI Ejecta volume Classification Description Plume Frequency Example Occurrences in last 10,000 years*
0 < 10,000 m³ Hawaiian non-explosive < 100 m daily Mauna Loamarker many
1 > 10,000 m³ Hawaiian/Strombolian gentle 100-1000 m daily Strombolimarker many
2 > 1,000,000 m³ Strombolian/Vulcanian explosive 1-5 km weekly Galerasmarker (1993) 3477*
3 > 10,000,000 m³ Vulcanian/Peléan severe 3-15 km yearly Cordón Caullemarker (1921) 868
4 > 0.1 km³ Peléan/Plinian cataclysmic 10-25 km ≥ 10 yrs Mount Peléemarker (1902) 278
5 > 1 km³ Plinian paroxysmal > 25 km ≥ 50 yrs Mount Agungmarker (1963) 84
6 > 10 km³ Plinian/Ultra-Plinian colossal > 25 km ≥ 100 yrs Lakimarker (1783) 39
7 > 100 km³ Plinian/Ultra-Plinian super-colossal > 25 km ≥ 1000 yrs Tamboramarker (1815) 5 (+2 suspected)
8 > 1,000 km³ Ultra-Plinian mega-colossal > 25 km ≥ 10,000 yrs Taupo (26,500 BP) 0


*Count of eruptions in the last 10,000 years are based on 1994 figures maintained by the Global Volcanism Program of the Smithsonian Institutionmarker.

A total of 47 eruptions of VEI–8 magnitude or above, ranging in age from Ordovician to Pleistocene, are identified, of which 42 eruptions are known from the past 36 million years. The most recent one is Lake Taupo's Oruanui eruption, occurring 26,500 years ago, which means that there have not been any Holocene (within the last 10,000 years) eruptions with a VEI of 8.

List of eruptions

VEI Volcano (eruption) Year
0 Hoodoo Mountainmarker 7050 BC?
Mauna Loamarker 1984
Piton de la Fournaisemarker 2004
1 Wells Gray-Clearwater volcanic fieldmarker 1500?
Kilaueamarker 1983 - present
Nyiragongo 2002
2 Mount Hoodmarker 1865-1866
Kilaueamarker 1924
Tristan da Cunhamarker 1961
Mount Usumarker 2000-2001
Whakaari/White Islandmarker 2001
3 Mount Garibaldimarker 9,300 BP
Nazko Conemarker 7,200 BP
Mount Edzizamarker 950 AD ± 1000 years
Mount Vesuviusmarker 1913-1944
Surtseymarker 1963-1967
Eldfellmarker 1973
Nevado del Ruizmarker 1985
Mount Etnamarker 2002-2003
4 Mount Peléemarker 1902
Parícutinmarker 1943-1952
Heklamarker 1947
Galunggungmarker 1982
Mount Spurrmarker 1992
Chaitenmarker 2008
Mount Okmokmarker 2008
5 Heklamarker (Hekla 3 eruption) 1021 + 130/-100 BC
Mount Meagermarker ≈400 BC (2350 BP)
Mount Vesuviusmarker (Pompeianmarker eruption) 79
Mount Edgecumbe/Pūtauakimarker c. 300
Mount Tarumaemarker 1739
Mount Taraweramarker 1886
Mount Agungmarker 1963
Mount St. Helensmarker 1980marker
El Chichónmarker 1982
Lake Nyosmarker 1986
Mount Hudsonmarker 1991
6 Morne Diablotinsmarker 30,000 BP
Nevado de Tolucamarker 10,500 BP
Mount Okmokmarker 8300 BP
Mount Etnamarker 8000 BP?
Mount Veniaminofmarker 1750 BC
Mount Vesuviusmarker (Avellino eruption) 1660 BC ± 43 years
Mount Aniakchakmarker ≈1645 BC
Mount Okmokmarker c. 400 BC
Ambrymmarker c. AD 100
Ilopangomarker 450 ± 30 years
Mount Churchillmarker (White River Ash) ≈750 (1200 BP)
Lakimarker (Eldgjámarker) 934
Baekdu Mountainmarker (Tianchi eruptionmarker) 969 ± 20 years
Kuwaemarker 1452 or 1453
Huaynaputinamarker 1600
Lakimarker 1783
Krakatoamarker 1883
Santa Maríamarker 1902
Novaruptamarker 1912
Mount Pinatubomarker 1991
7
Bennett Lake Volcanic Complex 50 Ma
Vallesmarker (Lower Bandelier eruption) 1.47 Ma
Yellowstone (Mesa Falls eruption) 1.3 Ma
Vallesmarker (Upper Bandelier eruption) 1.15 Ma
Long Valley Caldera (Bishop eruption) 759,000 BP
Manijau 280,000 BP
Atitlánmarker (Los Chocoyos eruption) 84,000 BP
Kurilemarker (Golygin eruption) 41,000 BP
Campi Flegreimarker 37,000 BP
Aira Calderamarker 22,000 BP
Laacher Seemarker 12,900 BP?
Kurilemarker (Ilinsky eruption) 6440 BC ± 25 years
Crater Lake, Oregonmarker (Mount Mazama eruptionmarker) 5677 BC ± 150 years
Kikai (Akahoya eruption) ≈5300 BC
Theramarker (Minoan eruptionmarker) 1620s BC
Taupomarker (Hatepe eruption) 186
Mount Tamboramarker 1815
8 Scafellsmarker Ordovician
Glen Coemarker 420 Ma
La Garita Calderamarker 27 Ma
Yellowstone (Huckleberry Ridge eruption) 2.2 Ma
Galánmarker 2.2 Ma
Yellowstone (Lava Creek eruption) 640,000 BP
Tobamarker 73,000 BP
Taupomarker (Oruanui eruption) 26,500 BP


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