Volcanic Explosivity Index

The Vulkanexplosivitätsindex (abbreviation VEI, Eng. Volcanic Explosivity Index ) is a logarithmic scale from 0 to 8 to indicate the strength of an explosive volcanic eruption. Measured variables are the amount of ejected volcanic loose material ( tephra ), the height of the eruption column and to a lesser extent qualitative descriptions. It was introduced in 1982 by the American geologist Chris Newhall and Stephen Self.

The scale is logarithmic constructed, each higher level describes a tenfold volcanic eruption, starting with a harmless volcanic event up to level eight as a gigantic eruption with global impact. The scale could, if necessary, be extended upward.

Scientists point out, however, that it is very difficult to measure the strength of volcanic eruptions really accurate.

Vulkanexplosivitätsindex

Note to the table: The tephra quantity increases by a factor of 10 with each VEI level. The only exception to this is the transition from 0 to VEI VEI 1, where the quantity increases by a factor of 100.

Historical examples

Thickness 8

Only twice reached a volcanic eruption within the last 100,000 years the strength of 8:

  • Taupo 26,500 years ago with 1170 km ³ tephra
  • Toba nearly 74,000 years ago, 2,800 km ³ of tephra

Magnitude 7

In the last 10,000 years there were probably five outbreaks of magnitude 7:

  • Kurilenseevulkan to 5700 BC, with 130 km ³ of tephra
  • Mount Mazama around 4895 BC, with 150 km ³ of tephra
  • Kikai around 4350 BC with over 150 km ³ of tephra
  • Taupo to 181 ³ with 85-100 km tephra
  • Tambora in 1815 ³ 160 km tephra

There are three disputed or borderline between the strengths outbreaks 6 and 7:

  • Santorini 1627 BC or 1520 BC with 30-70 km ³ of tephra
  • Ambrym by 50 70 km ³ of tephra
  • Paektusan 969 to 96 km ³ of tephra

Thickness 6

  • Pinatubo in 1991, with 10 km ³ of tephra
  • Novarupta, 1912, 13-15 km ³ of tephra
  • Santa María, 1902, at 20 km ³ tephra
  • Krakatau, 1883, ³ with 20 km of tephra
  • Huaynaputina, 1600 ³ 30 km of tephra
  • Kuwae, 1453, 32-39 km ³ of tephra
  • Laacher volcano to 11000-10900 BC, 16 km ³ of tephra

Thickness 5

  • Cerro Hudson, 1991, with 4.3 km ³ of tephra
  • Mount St. Helens, 1980, ³ 1.2 km of tephra
  • Mount Fuji, in 1707, at 2.1 km ³ of tephra
  • Parker, 1641, ³ with less than 1 km tephra
  • Vesuvius, 79, 3.3 km ³ with tephra
  • Etna, 122 BC

Strength 4

  • Eyjafjallajökull, 2010 ³ 0.14 km tephra
  • Mont Pelée, 1902, with 0.2 km ³ of tephra
  • Laki craters, 1783, 0.91 km ³ of tephra
  • Eldgjá, 934, 1.4 km ³ of tephra

Other classification methods of volcanic eruptions

  • Tsuya classes: classification similar to the VEI in classes I to IX.
  • Haze: The turbidity index has a value of 1000 for the Krakatoa eruption of 1883 and serves as a parameter to describe the volcanic disturbances in atmospheric layers, which can then affect the climate,
  • VPI: Volcano Population Index: The index indicates how many people live in a volcanic eruption within a certain radius from the location of the outbreak in a hazardous area. Are often used VPI5 and VPI10 available for CPIs with a radius of 5 km or 10 km, the relevant areas of outbreaks with VEI 2 to 4
Nevado del Ruiz Taupo Volcano Kurile Lake Crater Lake Laacher See Mount Hudson
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