Volcanic Explosivity Index 32700 225357173 2008-07-13T07:20:57Z Orangemarlin 114927 Reverted 1 edit by [[Special:Contributions/84.61.200.46|84.61.200.46]] identified as [[WP:VAND|vandalism]] to last revision by [[User:Bender235|Bender235]].using [[WP:TWINKLE|TW]] [[Image:VEIfigure en.svg|thumb|270px|VEI and ejecta volume correlation]] The '''Volcanic Explosivity Index''' (VEI) was devised by [[Christopher G. Newhall|Chris Newhall]] of the [[U.S. Geological Survey]] and [[Stephen Self (geologist)|Steve Self]] at the [[University of Hawaii at Manoa|University of Hawai{{okina}}i]] in [[1982]] to provide a relative measure of the explosiveness of [[volcano|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 10<sup>4</sup> cubic metres of [[tephra]] ejected) with 8 representing a mega-colossal explosive eruption that can eject 10<sup>12</sup> cubic metres of [[tephra]] and have a cloud column height of over {{convert|25|km|mi|abbr=on|lk=off}}. Each interval on the scale represents a tenfold increase in observed eruption criteria. Note that [[Volcanic ash|ash]], [[volcanic bomb]]s, 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 measure how powerful volcanic eruptions are using the VEI. The VEI stands for Volcanic Explosivity Index. It records how much volcanic matierial is thrown out, how high the eruption goes, and how long it lasts. The scale goes from 0 to 8. A score of 1 is 10 times more powerful than a score of 0. {| class="wikitable" !VEI !Classification !Description !Plume !Ejecta volume !Frequency !Example !Occurrences * |- ! 0 |[[Hawaiian Eruption|Hawai{{okina}}ian]] || non-explosive || &lt; 100 m || &lt; 10,000 m³ || daily || [[Mauna Loa]] || many |- ! 1 | Hawai{{okina}}ian/[[Strombolian Eruption|Strombolian]] || gentle || 100-1000 m || &gt; 10,000 m³ || daily || [[Stromboli]] || many |- ! 2 | Strombolian/Vulcanian || explosive || 1-5 km || &gt; 1,000,000 m³ || weekly || [[Galeras]] ([[1993]])|| 3477* |- ! 3 | [[Vulcanian Eruption|Vulcanian]]/Pelean || severe || 3-15 km || &gt; 10,000,000 m³ || yearly || [[Koryaksky]] || 868 |- ! 4 | [[Peléan eruption|Pelean]]/Plinian|| cataclysmic || 10-25 km || &gt; 0.1 km³ || ≥ 10 yrs || [[Soufrière Hills]] ([[1995]])|| 278 |- ! 5 | [[Plinian eruption|Plinian]] || paroxysmal || &gt; 25 km || &gt; 1 km³ || ≥ 50 yrs || [[Mount St. Helens|St. Helens]] ([[1980]])|| 84 |- ! 6 | Plinian/Ultra-Plinian || colossal|| &gt; 25 km || &gt; 10 km³ || ≥ 100 yrs || [[Mount Pinatubo]] ([[1991]])|| 39 |- ! 7 | Plinian/Ultra-Plinian || super-colossal || &gt; 25 km || &gt; 100 km³ || ≥ 1000 yrs || [[Mount Tambora|Tambora]] ([[1815]])|| 5 (+2 suspected) |- ! 8 | Ultra-Plinian || mega-colossal || &gt; 25 km || &gt; 1,000 km³ || ≥ 10,000 yrs || [[Lake Toba|Toba]] (73,000 [[Before present|BP]])|| 1 |} ''* Count of eruptions in the last 10,000 years based on 1994 figures maintained by the Global Volcanism Program of the [[Smithsonian Institution]]'' Note that 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. ==List of eruptions== {{listdev}} {| class="wikitable" !VEI !Name !Year |- !rowspan=3|0 | [[Mauna Loa]] || [[1984]] |- | [[Piton de la Fournaise]] || [[2004]] |- | [[Hoodoo Mountain]] || 7050 BC? |- !rowspan=3|1 | [[Kilauea]] || [[1983]] - present |- | [[Nyiragongo]] || [[2002]] |- | [[Wells Gray-Clearwater Volcanic Field]] || [[1500]]? |- !rowspan=5|2 | [[Mount Hood]] || [[1865]]-[[1866]] |- | [[Kilauea]] || [[1924]] |- | [[Tristan da Cunha]] || [[1961]] |- | [[Whakaari/White Island]] || [[2001]] |- | [[Mount Usu]] || [[2000]]-[[2001]] |- !rowspan=8|3 | [[Mount Vesuvius]] || [[1913]]-[[1944]] |- | [[Mount Edziza]] || 950 AD ± 1000 years |- | [[Surtsey]] || [[1963]]-[[1967]] |- | [[Eldfell]] || [[1973]] |- | [[Nevado del Ruiz]] || [[1985]] |- | [[Mount Etna]] || [[2002]]-[[2003]] |- | [[Mount Garibaldi]] || 9,300 [[Before Present|BP]] |- | [[Nazko Cone]] || 7,200 [[Before Present|BP]] |- !rowspan=5|4 | [[Mount Pelée]] || 1902 |- | [[Parícutin]] || [[1943]]-[[1952]] |- | [[Hekla]] || [[1947]] |- | [[Galunggung]] || [[1982]] |- | [[Mount Spurr]] || [[1992]] |- !rowspan=9|5 | [[Hekla]] ([[Hekla 3 eruption]]) || [[1159 BC]] |- | [[Mount Vesuvius]] ([[Pompeii]] eruption) || [[79]] |- | [[Mount Tarumae]] || [[1739]] |- | [[Mount Agung]] || [[1963]] |- | [[Mount St. Helens]] ([[1980 Mount St. Helens eruption|1980 eruption]]) || [[1980]] |- | [[Mount Meager]] || 2350 [[Before Present|BP]] |- | [[El Chichón]] || [[1982]] |- | [[Mount Hudson]] || [[1991]] |- | [[Mount Tarawera]] || [[1886]] |- !rowspan=15|6 | [[Mount Etna]] <!-- VEI 6+ --> || 8000 [[before present|BP]]? |- | [[Mount Veniaminof]] <!-- VEI 6+ --> || [[1750 BC]] |- | [[Mount Vesuvius]] ([[Avellino eruption]]) <!-- VEI 6+ --> || [[1660s BC|1660 BC]] ± 43 years |- | [[Thera]] ([[Minoan eruption]]) <!-- 30-60 cubic km = VEI 6.5 --> || [[1620s BC]] or [[1520s BC]] |- | [[Mount Churchill]] ([[White River Ash]]) || 1200 [[Before Present|BP]] |- | [[Ilopango (volcano)|Ilopango]] || [[450]] ± 30 years |- | [[Laki]] <!-- 19.6 cubic km == VEI 6.3 --> || [[934]] |- | [[Baekdu Mountain]] ([[Tianchi eruption]]) <!-- 90 cubic km == VEI 6.9 --> || ≈[[1200]] |- | [[Kuwae]] || [[1452]] or 1453 |- | [[Huaynaputina]] || [[1600]] |- | [[Laki]] <!-- 20 cubic km == VEI 6.3 --> || [[1783]] |- | [[Krakatoa]] <!-- 30 cubic km == VEI 6.5 --> || [[1883]] |- | [[Santamaría (volcano)|Santa María]] <!-- 5-20 cubic km == VEI 6 --> || [[1902]] |- | [[Novarupta]] <!-- 30 cubic km == VEI 6.5 --> || [[1912]] |- | [[Mount Pinatubo]] <!-- 10 cubic km = VEI 6.0 --> || [[1991]] |- !rowspan=9|7 | [[Bennett Lake Volcanic Complex]] <!-- 850 cubic km = VEI 7.0 --> || 50 [[Annum|Ma]] |- | [[Yellowstone Caldera|Yellowstone]] ([[Mesa Falls Tuff|Mesa Falls eruption]]) <!-- 700 cubic km = VEI 7+ --> || 1.3 Ma |- | [[Long Valley Caldera]] <!-- 550 cubic km = VEI 7.75 --> || 760,000 [[Before Present|BP]] |- | [[Aira Caldera]] <!-- 400 cubic km = VEI 7.5 --> || 22,000 BP |- | [[Kurile Lake|Kurile]] <!-- VEI 7 --> || [[6440 BC]] ± 25 years |- | [[Crater Lake National Park|Crater Lake, Oregon]] ([[Mount Mazama|Mount Mazama eruption]]) <!-- 104 cubic km = VEI 7.0 --> || ≈[[4860 BC]] |- | [[Kikai Caldera|Kikai]] ([[Akahoya eruption]]) <!-- 150 cubic km = VEI 7.0 --> || ≈[[4350 BC]] |- | [[Lake Taupo|Taupo]] ([[Hatepe eruption]]) <!-- 100-120 cubic km = VEI 7.0 --> || ≈[[180]] |- | [[Mount Tambora]] <!-- 100-150 cubic km = VEI 7.0 --> || [[1815]] |- !rowspan=6|8 | [[La Garita Caldera]] <!-- 5,000 cubic km = VEI 8.6 --> || 27 Ma |- | [[Yellowstone Caldera|Yellowstone]] ([[Huckleberry Ridge Tuff|Huckleberry Ridge eruption]]) <!-- 2500 cubic km = VEI 8.4 --> || 2.2 Ma |- | [[Galán]] <!-- 1050 cubic km = VEI 8.0 --> || 2.2 Ma |- | [[Yellowstone Caldera|Yellowstone]] ([[Lava Creek Tuff|Lava Creek eruption]]) <!-- 1000 cubic km = VEI 8.0 --> || 640,000 [[Before Present|BP]] |- | [[Lake Toba|Toba]] <!-- 2800 cubic km = VEI 8.45 --> || 73,000 [[Before Present|BP]] |- | [[Lake Taupo|Taupo]] ([[Oruanui eruption]]) <!-- 1170 cubic km = VEI 8.1 --> || 26,500 [[Before Present|BP]] |- |} Note that there have not been any [[Holocene]] (within the last 10,000 years) eruptions with a VEI of 8. Lake Taupo's [[Oruanui eruption]] is probably the most recent, occurring 26,500 years ago. ==See also== *[[Supervolcano]] *[[List of volcanoes]] *[[List of deadliest natural disasters]] ==Footnotes== {{reflist}} ==References== *{{cite journal | first = Christopher G. | last = Newhall | coauthors = Self, Steve | year = 1982 | title = The volcanic explosivity index (VEI): An estimate of explosive magnitude for historical volcanism | journal = [[Journal of Geophysical Research]] | volume = 87 | issue = C2 | pages = 1231&ndash;1238 | url = http://www.agu.org/pubs/crossref/1982/JC087iC02p01231.shtml | doi = 10.1029/JC087iC02p01231 }} *{{cite journal | first = Ben G. | last = Mason | coauthors = Pyle, David M.; Oppenheimer, Clive | year = 2004 | title = The size and frequency of the largest explosive eruptions on Earth | journal = Bulletin of Volcanology | volume = 66 | issue = 8 | pages = 735&ndash;748 | doi = 10.1007/s00445-004-0355-9 }} ==External links== * [http://volcanoes.usgs.gov/Products/Pglossary/vei.html VEI glossary entry] from a [[United States Geological Survey|USGS]] website * [http://talk.workunlimited.co.uk/life/feature/story/0,13026,1294868,00.html How to measure the size of a volcanic eruption], from ''[[The Guardian]]'' * [http://springerlink.metapress.com/openurl.asp?genre=article&doi=10.1007/s00445-004-0355-9 The size and frequency of the largest explosive eruptions on Earth], a 2004 article from the ''[[Bulletin of Volcanology]]'' * [http://www.volcano.si.edu/world/largeeruptions.cfm List of Large Holocene Eruptions (VEI > 4) from the Smithsonian Global Volcanism Program] [[Category:Volcanology]] [[Category:Scales]] [[de:Vulkanexplosivitätsindex]] [[es:Índice de Explosividad Volcánica]] [[fa:نمایه شدت فوران آتشفشان]] [[fr:Indice d'explosivité volcanique]] [[id:Volcanic Explosivity Index]] [[it:Indice di esplosività vulcanica]] [[hu:Volcanic Explosivity Index]] [[nl:Vulkanische Explosiviteits Index]] [[no:Volcanic Explosivity Index]] [[nn:Vulkaneksplosivitetsindeks]] [[pl:Indeks Eksplozywności Wulkanicznej]] [[simple:Volcanic Explosivity Index]] [[sv:VEI-skalan]]