Kolumbo Volcano, Greece: expert elicitation findings supporting volcanic hazard and risk assessment

A detailed hazard and risk assessment project has been undertaken for Kolumbo Volcano, an active volcano situated in the Aegean Sea, Greece. In support, a comprehensive structured expert judgement exercise was conducted using the Classical Model for pooling specialists' uncertainty quantifications concerning Target Item questions concerning volcanological model parameters, empirical variables and event probabilities of interest. In total, 64 Target Items, organised according to a new event tree model for Kolumbo Volcano, were elicited from thirteen specialists who participated in two workshops (part of a group of fifteen in total who attended and contributed to at least one session). Related statistical distributions and associated uncertainties were quantified via ELICIPY, a recently released Python version of the Classical Model algorithm. The overarching methodological approach is summarised and a number of examples of ELICIPY solutions for specific Target Items are given, illustrating the nature and key probabilistic features of such results; these statistical characterizations provide direct inputs to various hazard and risk models for a potential near-future eruption of Kolumbo Volcano. In addition, a new type of elicitation metric, the 'Conformity Score', is introduced in two alternative formulations for ranking the item-wise extents of agreement/disagreement between experts providing judgments; these rankings help inform stake holders which specific Target Items are well-constrained by expert elicitation, while also identifying where possible major knowledge gaps among experts may exist on other topics of interest.