Volcanic explosivity index

It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982.

Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value.

A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m3 (350,000 cu ft) of tephra ejected; and 8 representing a supervolcanic eruption that can eject 1.0×1012 m3 (240 cubic miles) of tephra and have a cloud column height of over 20 km (66,000 ft).

In contrast, the DRE (dense-rock equivalent) is sometimes calculated to give the actual amount of magma erupted.

Although VEI is quite suitable for classifying the explosive magnitude of eruptions, the index is not as significant as sulfur dioxide emissions in quantifying their atmospheric and climatic impact.

VEI and ejecta volume correlation
2011 Puyehue-Cordón Caulle eruption 1980 eruption of Mount St. Helens 1912 eruption of Novarupta Yellowstone Caldera AD 79 Eruption of Mount Vesuvius 1902 eruption of Santa María 1280 eruption of Quilotoa 1600 eruption of Huaynaputina 2010 eruptions of Eyjafjallajökull Yellowstone Caldera 1783 eruption of Laki 1477 eruption of Bárðarbunga 1650 eruption of Kolumbo Volcanic activity at Santorini Toba catastrophe theory Kuril Islands Baekdu Mountain Kikai Caldera 1991 eruption of Mount Pinatubo Long Island (Papua New Guinea) 1815 eruption of Mount Tambora 1883 eruption of Krakatoa 2010 eruptions of Mount Merapi Billy Mitchell (volcano) Taupō Volcano Taupō Volcano Taupō Volcano Crater Lake
Clickable imagemap of notable volcanic eruptions . The apparent volume of each bubble is linearly proportional to the volume of tephra ejected, colour-coded by time of eruption as in the legend. Pink lines denote convergent boundaries , blue lines denote divergent boundaries and yellow spots denote hotspots .