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ERUPTION STYLES, SCALES, AND FREQUENCIES 155

Table 10.3 The Volcanic Explosivity Index (VEI) classification scheme.

Volcanic Explosivity General eruption Qualitative eruption Erupted volume Eruption column
3
Index description description (m ) height (km)
0 Nonexplosive “Gentle, effusive” < 10 4 < 0.1
1 Small “Gentle, effusive” 10 6 0.1–1
2 Moderate “Explosive” 10 7 1–5
3 Moderate/large “Explosive” 10 8 3–15
4 Large “Explosive” 10 9 10–25
5 Very large “Cataclysmic, 10 10 > 25
6 Very large paroxysmal, 10 11 up
7 Very large or 10 12 to
8 Very large colossal” > 10 12 ∼55

Table 10.4 The magnitude, intensity and Volcanic Explosivity Index (VEI) of a number of historical eruptions: M is the total
e
erupted mass and M the peak mass flux.
f
−1
Eruption Erupted M (kg) M (kg s ) Column VEI Magnitude Intensity
e f
3
volume (km ) height (km)
Etna (Italy) 1991–1993 0.25 5 × 10 11 6 × 10 4 ∼1 2 4.7 7.8
Pinatubo (Philippines) 1991 7.5 1.1 × 10 13 4 × 10 8 35 6 6 11.6
Mount St Helens (USA) 1980 1.2 1.3 × 10 12 2 × 10 7 19 5 4.8 10.3
Soufriere (St Vincent) 1979 0.05 10 11 3 × 10 7 18 3 4 10.5
Kilauea (USA) 1959 0.03 6.6 × 10 10 1.5 × 10 5 > 0.6 2 3.8 8.2
Bezymianny (Russia) 1956 ∼2 10 12 2.2 × 10 8 36 5 5.3 11.3
Mauna Loa (USA) 1950 0.39 10 12 7 × 10 6 ? 0 5 9.8
Novarupta (Alaska) 1912 15 3 × 10 13 1 × 10 8 25 6 6.5 11.0
Santa Maria (Guatemala) 1902 12 2 × 10 13 1.7 × 10 8 34 6 6.3 11.2
Tarawera (New Zealand) 1886 2 2 × 10 12 2.2 × 10 8 34 5 5.3 11.3
Krakatau (Indonesia) 1883 > 10 3 × 10 13 ∼5 × 10 7 25 6 6.5 10.7
Askja (Iceland) 1875 0.17 ∼10 11 8 × 10 7 26 4 4.0 10.9
Tambora (Indonesia) 1815 > 50 2 × 10 14 2.8 × 10 8 43 7 7.3 11.4
Laki (Iceland) 1783 15 3 × 10 13 2.4 × 10 7 12 4 6.5 10.4
Taupo (New Zealand) ∼ AD 180 35 8 × 10 13 1.1 × 10 9 51 6+ 6.9 12.0
Vesuvius (Italy) AD 79 6 6 × 10 12 1.5 × 10 8 32 6 5.8 11.2

Data taken from Richter, D.H., Eaton, J.P., Murata, K.J., Ault, W.U. and Krivoy, H.L. (1970) Chronological narrative of the
1959–60 eruption of Kilauea Volcano, Hawai’I. U.S. Geol. Surv. Prof. Pap., 537-E, 73 pp.; Sparks, R.S.J., Wilson, L. and
Sigurdsson, H. (1981) The pyroclastic deposits of the 1875 eruption of Askja, Iceland. Philos. Trans. Roy. Soc. London Ser. A,
299, 241–273; Wadge, G. (1981) The variation of magma discharge during basaltic eruptions. J. Volcanol. Geotherm. Res., 11,
139–168; Newhall & Self (1982); Sparks, R.S.J. and Wilson, L. (1982) Explosive volcanic eruptions – V. Observations of plume
dynamics during the 1979 Soufriere eruption, St Vincent. Geophys. J. Roy. Astron. Soc., 69, 551–570; Walker, G.P.L., Self, S.
and Wilson, L. (1984) Tarawera 1886, New Zealand – a basaltic plinian fissure eruption. J. Volcanol. Geotherm. Res., 21,
61–78; Cas, R.A.F. and Wright, J.V. (1987) Volcanic Successions – Modern and Ancient. Chapman and Hall, London, 528 pp.;
Wilson, L. and Walker, G.P.L. (1987) Explosive volcanic eruptions – VI. Ejecta dispersal in Plinian eruptions – the control of
eruption conditions and atmospheric properties. Geophys. J. Roy. Astron. Soc., 89, 657–679; Pyle, D.M. (1989) The thickness,
volume and grainsize of tephra fall deposits. Bull. Volcanol., 51, 1–15; Simkin, T. and Seibert, L. (1994) Volcanoes of the
World. Geoscience Press, 349 pp.; Parfitt, E.A. (1998) A study of clast size distribution, ash deposition and fragmentation in a
Hawaiian-style volcanic eruption. J. Volcanol. Geotherm. Res., 84, 197–208; and Pyle (2000).