Reducing the volcanic risk in the frame of the hazard/risk separation principle

Abstract

Reducing the impact of volcanic eruptions on society is a major challenge of volcanology. Although science is one basic component of risk reduction, the achievement of this goal requires competencies that go beyond natural sciences. Nowadays, the importance of non-scientific factors in reducing volcanic risks is often and dangerously overlooked, possibly leading to decision making that cannot be rationally justified. In this paper we explore the basic components of an ideal decision-making process, identifying the roles and responsibilities of the different partners/tasks that are involved. In particular, we advocate the use of the hazard/risk separation principle, which can help discern unambiguously the role of volcanology (and more in general of science) in the whole risk-reduction process. Although this distinction may be of low relevance in some real cases—for example, when the costs of mitigation actions are low and the likelihood of eruption is high—it becomes of paramount importance when dealing with high uncertainty on the eruption onset or size and expensive mitigation actions, such as the evacuation of a large city. Volcanologists can play different roles in the decision-making process, but they have to be aware that this demands competencies that go beyond being a good volcano scientist. The final intent of this paper is to encourage constructive cooperation between volcanologists and public-policy makers keeping separated their own tasks as defined by their roles and their competences, with the intent of establishing fully transparent decision-making protocols well before volcanic crises. These protocols can be very helpful to audit the decision-making process at any time, and they may be an excellent communication tool for the interested stakeholders, including society.