Statistical analysis of the historical activity of Mount Etna, aimed at the evaluation of volcanic hazard

We analyzed the space–time distribution of the lateral eruptions of Mt Etna during the last 5centuries aimed at the definition of the probability of eruption, and proposed a method to make quantitative estimate of lava flow hazard. The time series analysis shows that, on average, the temporal distribution of flank eruptions follows a non-homogeneous Poisson distribution. The last 20 years of activity point out to an increasing number of eruptions with time. The lava flows can be divided into two classes: those with a short duration and high effusion rate (type I flows), and those with relatively lower effusion rates, but longer durations (type II flows). Type I flows attain the longest lengths. We evaluate the probability of a given lava flow length for Type I events, based on the distribution of historical lava flow fields, and the duration and effusion rate of the corresponding eruption. We propose a methodology for the evaluation of hazard from lava flow, taking into account the worst-case scenario of a type I lava flow, and the probability that it can reach a certain area, basing on the probability of occurrence of eruption, of location of the vent, and of flow length.