From: Evaluating life-safety risk for fieldwork on active volcanoes: the volcano life risk estimator (VoLREst), a volcano observatory’s decision-support tool
Eruption Size
Description
Percentile
Large
1 out of 100 eruptions at least this size
> 99
Moderate
1 out of 10 eruptions at least this size
90–99
Small
9 out of 10 eruptions this size
< 90