An index published in 1982 by Christopher Newhall and Stephen Self, for rating the explosivity of volcanic eruptions.¹ Acronym, VEI.
1. Christopher G. Newhall and Stephen Self.
The volcanic explosivity index (VEI): An estimate of explosive magnitude for historical volcanism.
Journal of Geophysical Research, volume 87 number C2, pages
1231-1238 (20 February 1982).
Criteria¹ | Volcanic Explosivity Index | ||||||||
---|---|---|---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | |
Description | non-explosive | small | moderate | moderate to large | large | very large | |||
Volume of ejecta (cubic meters) |
<10⁴ | 10⁴– 10⁶ |
10⁶– 10⁷ |
10⁷– 10⁸ |
10⁸– 10⁹ |
10⁹– 10¹⁰ |
10¹⁰– 10¹¹ |
10¹¹– 10¹² |
>10¹² |
Tsuya class² | I | II-III | IV | V | VI | VII | VIII | IX | |
Column height (kilometers)³ |
<0.1 | 0.1-1 | 1-5 | 3-15 | 10-25 | >25 | |||
Qualitative description |
gentle, effusive | explosive | cataclysmic, paroxysmal, colossal | ||||||
severe, violent, terrific | |||||||||
Classifications | Strombolian | Plinian | |||||||
Hawaiian | Vulcanian | Ultraplinian | |||||||
Duration of continuous blast (hours) |
<1 | >12 | |||||||
1-6 | |||||||||
6-12 | |||||||||
CAVW maximum explosivity⁴ |
lava flows | explosion or nuée ardente | |||||||
phreatic | |||||||||
dome or mudflow | |||||||||
Tropospheric injection |
negligible | minor | moderate | substantial | |||||
Stratospheric injection |
none | none | none | possible | definite | significant |
After Newhall and Self.
1. Criteria are listed in decreasing order of reliability.
2. Tsuya classification (based on volume of ejecta), assuming pyroclastic flows. The scale is defined in:
H. Tsuya.
Geological and petrological studies of volcano Fuji, 5.
Tokyo Daigaku Jishin Kenkyusho Iho, volume 33, pages 3-382 (1955).
3. For VEI's 0 – 2, measured from the crater rim; for VEI's 3 – 8, measured from sea level.
4. Most explosive activity indicated for the eruption in the Catalog of Active Volcanoes of the World.
Volcano | Date of Eruption | VEI |
---|---|---|
Kilauea, Hawaii, U.S. |
almost continuous | 0 |
Nyiragongo, Dem. Rep. of Congo |
began 17 January 2002 | 1 |
Soufriere Hills, Montserrat |
began 18 July 1995 | 3 |
Eyjafyallajökull, Iceland |
2010 | 4 |
Mt. St. Helens U.S. |
18 May 1980 | 5 |
Mt. St Helens, U.S. |
1540 ± 70 | 5 |
Krakatau, Indonesia |
26 Aug 1883 | 6 |
Tambora, Indonesia |
5 April 1815 | 7 |
Samalas, Indonesia |
1257 | 7 |
Yellowstone, U.S. |
1.3 million years ago, 2.8 × 10¹¹ |
7 |
Yellowstone, U.S. |
630,000 years ago, 1 × 10¹² |
8 |
Yellowstone, U.S. |
2 million years ago, 2.5 × 10¹² |
8 |
Note: Because of the open-ended nature of the scale, for the Yellowstone eruptions we have provided the volume of ejecta in cubic meters as estimated by the U.S. Geological Survey.
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Last revised: 21 October 2013.