The scale for classifying volcanic eruptions may underplay the danger of weak explosions.
A team led by Bruce Houghton at the University of Hawaii in Honolulu studied material that erupted in 2008 from Kīlauea volcano, Hawaii. The largest eruption shot out 310 cubic metres of ash and rock, but ranked only as a category 0 — the lowest possible on the Volcanic Explosivity Index, which is based mainly on how much material is ejected.
Although category 0 is described as non-explosive, the 2008 Kīlauea eruptions were not — they were just low volume. The authors propose splitting the existing category 1 into two, and adding categories down to −6.
Such adjustments could permit more accurate descriptions of small eruptions and allow hazard managers to better communicate the risk to people living near or visiting volcanoes.
Geology http://dx.doi.org/10.1130/G34146.1 (2013)