Volcanic Explosivity Index
In volcanology, the Volcanic Explosivity Index (VEI) is the way to measure the strength of a volcanic eruption. The Volcanic Explosivity Index measures how large or strong volcanic eruptions are. The index is a scale of 0 to 8. 0 is very small, and 8 is huge and very rare.
The largest eruption in modern times, the 1980 eruption of Mount St. Helens, was a 5 on the index. The Oruanui eruption of the Taupo Volcano in New Zealand was the world’s largest known eruption in the past 70,000 years was an 8. Another eruption of the Taupo volcano happened about 1,800 years ago. It was the most violent eruption in the world in the last 5,000 years. Mt Tambora was a 7 on the Volcanic Explosivity Index. Supervolcanoes have a Volcanic Explosivity Index of 8; and if the definition is expanded, also include volcanoes with a Volcanic Explosivity Index of 7.
| VEI | Ejecta volume (bulk) |
Classification | Description | Plume | Periodicity | Tropospheric injection |
Stratospheric injection[1] |
|---|---|---|---|---|---|---|---|
| Examples | |||||||
| 0 | < 104 m3 | Hawaiian | Effusive | < 100 m | constant | negligible | none |
| Kīlauea (current), Mawson Peak (current), Dallol (2011), Holuhraun (2014-2015), Fagradalsfjall (2021-2023), Mauna Loa (1975, 1984, 2022) | |||||||
| 1 | > 104 m3 | Hawaiian / Strombolian | Gentle | 100 m – 1 km | daily | minor | none |
| Yakedake (1995), Raoul Island (2006), Havre Seamount (2012), Dieng Volcanic Complex (1964, 1979, 2017), Nyiragongo (1977, 2002, 2021) | |||||||
| 2 | > 106 m3 | Strombolian / Vulcanian | Explosive | 1–5 km | 2 weeks | moderate | none |
| Stromboli (since 1934), Etna (current), Unzen (1792), Ruang (1871), Ritter Island (1888), Galeras (1993), Whakaari / White Island (2019) | |||||||
| 3 | > 107 m3 | Strombolian / Vulcanian / Peléan / Sub-Plinian | Severe | 3–15 km | 3 months | substantial | possible |
| 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 |
| 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 |
| 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 |
| Santorini (1620 BC), Lake Ilopango (450), Huaynaputina (1600), Krakatoa (1883), Santa Maria (1902), Novarupta (1912), Pinatubo (1991) | |||||||
| 7 | > 100 km3 | Ultra-Plinian | Super-colossal | > 20 km | 500–1,000 years | substantial | substantial |
| Long Valley (760 kyr), Campi Flegrei (37 kyr), Aira (22 kyr), Mazama (5700 BC), Kikai (4300 BC), Samalas (1257), Tambora (1815) | |||||||
| 8 | > 1,000 km3 | Ultra-Plinian | Mega-colossal | > 20 km | > 50,000 years[2][3] | vast | vast |
| 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 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,[2] 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.[4][5] The most recent is Lake Taupō's Oruanui eruption, more than 27,000 years ago, which means that there have not been any Holocene eruptions with a VEI of 8.[4]
References
[change | change source]- ↑ "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.
- ↑ 2.0 2.1 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.
- ↑ Rothery, David A. (2010), Volcanoes, Earthquakes and Tsunamis, Teach Yourself
- ↑ 4.0 4.1 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. 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.
Further reading
[change | change source]- Newhall, Christopher G.; Self, Stephen (1982). "The volcanic explosivity index (VEI): An estimate of explosive magnitude for historical volcanism". Journal of Geophysical Research. 87 (C2): 1231–1238. Bibcode:1982JGR....87.1231N. doi:10.1029/JC087iC02p01231.
- 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.
Other websites
[change | change source]- VEI glossary entry Archived 2007-10-08 at the Wayback Machine from a USGS website
- How to measure the size of a volcanic eruption Archived 2007-03-12 at the Wayback Machine, from The Guardian
- The size and frequency of the largest explosive eruptions on Earth[permanent dead link], a 2004 article from the Bulletin of Volcanology
- List of Large Holocene Eruptions (VEI > 4) from the Smithsonian Global Volcanism Program Archived 2012-01-17 at the Wayback Machine
