The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism

Abstract

Knowledge of the frequencies of highly explosive, moderately explosive, and nonexplosive eruptions would be useful in a variety of volcano studies. Historical records are generally incomplete, however, and contain very little quantitative data from which explosive magnitude can be estimated. Only the largest eruptions have a complete record back to the early 19th Century; other important explosive events went unrecorded prior to about 1960. Only a handful of the very biggest eruptions are represented in the geologic record, so it will be impossible to augment historical records post facto. A composite estimate of the magnitude of past explosive eruptions, termed the Volcanic Explosivity Index (VEI), is proposed as a semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism. The VEI has been assigned to over 8000 historic and prehistoric eruptions, and a complete list is available in a companion document.

Deposits, character and timing of recent eruptions and gravitational collapses in Tatun Volcanic Group, Northern Taiwan: Hazard-related issues

“…The erupted magma volume can roughly be estimated at 0.1-0.3 km 3 . Based on the grain size and volume of the deposit, we suggest that the eruption was of VEI 4 scale, with an eruption column approximately 15-20 km high (Newhall and Self, 1982;Pyle, 1989).…”

Perennial snow and ice volumes on Iliamna Volcano, Alaska, estimated with ice radar and volume modeling

“…The devastating mudflows generated by the 1980 eruption of Mount St. Helens, in Washington State, emphasized the need for information about the volume and distribution of snow and ice on volcanoes (Driedger and Kennard, 1986). However, the relation between the volume distribution of perennial snow and ice, volcanic explosivity (Newhall and Self, 1982), and lahar and flood hazards is poorly defined in the scientific literature. Nevertheless, it is apparent that increasing the area covered by snow and ice generally increases the potential for initiating lahars and floods during eruptions.…”

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

“…After the eruption of Mount Pinatubo in 1991, with a large Volcanic Explosivity Index (VEI) (Newhall and Self, 1982) of 6, the global, tropospheric temperature was estimated to have been 0.5 • C lower than the climatological average temperature. Another large eruption in Tambora (1815, VEI 7) caused an estimated drop in global mean temperature of 0.4 to 0.7 • C (McCormick et al, 1995).…”