An index rating the hazard level of a volcano based on how often it has erupted in the past, the average and maximum Volcanic Explosivity Index ratings of those eruptions, and the extent of pyroclastic, mud, or lava flows in the eruptions. When the index was introduced in 2015, historical records and geological data were good enough to permit calculating VHI scores for 328 volcanoes, about half of the existing active volcanoes.
The scores for classified volcanoes range from 0 to 30. A one-point difference in scores is hardly meaningful given the nature of some of the data used to arrive at the scores, so they were lumped into three more meaningful levels.
|Hazard Level||Score||Number of
|VHI I||0 to <8||134|
|VHI II||8 to <16||106|
The authors state (page 56) that the "VHI is too coarse for local use, but is a useful indicator of regional and global threat." To use the VHI Hazard Level rating it is combined with the Population Exposure Index (PEI), which rates a volcano on the number of people in the vicinity. The PEI has 7 levels. A volcano then falls in one of (3 VHI × 7 PEI =) 21 cells in a VHI/PEI matrix. If all the volcanoes in a country are marked on such a matrix, a reliable picture of the population's susceptibiity to volcanic disaster is produced. Indonesia, for example, is clearly at great risk.
|Nevado del Ruiz||III||5|
Googling any of these names will reveal a wealth of online resources about that volcano.
M. R. Auker, R. S. J. Sparks, S F. Jenkins, S. K. Brown, W. Aspinall, N. I. Deligne, G. Jolly, S. C. Loughlin, W. Marzocchi, C. G. Newhall and J. L. Palma.
CS19. Development of a new global volcanic hazard index (VHI).
S. K. Brown, S. C. Loughlin, R. S. J. Sparks, C. Vye-Brown, et al.
Global volcanic hazards and risk: Technical background paper for the Global Assessment Report on Disaster Risk Reduction 2015.
Global Volcano Model and IAVCEI. (2015)
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Last revised: 16 March 2017.