Volcanic Explosivity Index |
The Volcanic Explosivity Index (VEI) was devised by Chris Newhall of the U.S. Geological Survey and Steve Self at the University of Hawaii in 1982
to provide a relative measure of the explosiveness of volcanic eruptions.
Volume of products, eruption cloud height, and qualitative observations (from Gentle to Cataclysmic) are used to determine the
explosivity value. The scale is open-ended and ranges from 0, for non-explosive eruptions (less than 104 cubic metres of tephra ejected), to 8, for cataclysmic explosive
eruptions that can eject (1012 cubic metres of tephra and a cloud column height of over 25 km).
Values higher than 8 can be determined if needed.
VEI Index
|
VEI
|
Plume Height
|
Volume Ejected
|
How Often
|
Example
|
| 0 |
<100 m |
>1000 m3 |
daily |
Kilauea |
| 1 |
100–1000 m |
>10,000 m3 |
daily |
Stromboli |
| 2 |
1–5 km |
>1,000,000 m3 |
weekly |
Galeras, 1992 |
| 3 |
3–15 km |
>10,000,000 m3 |
yearly |
Ruiz, 1985 |
| 4 |
10–25 km |
>0.1 km3 |
>10 yrs |
Galunggung, 1982 |
| 5 |
>25 km |
>1 km3 |
>100 yrs |
St. Helens, 1981 |
| 6 |
>25 km |
>10 km3 |
>100 yrs |
Krakatau, 1883 |
| 7 |
>25 km |
>100 km3 |
>1000 yrs |
Tambora, 1815 |
| 8 |
>25 km |
>1000 km3 |
>10,000 yrs |
Toba, 71 ka |
| VEI |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
| Total Historic Eruptions |
487 |
623 |
3176 |
733 |
119 |
19 |
5 |
2 |
1 |
See also:
References: Newhall and Self (J. Geophys. Research, v. 87, p. 1231–1238, 1982)
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