IRIVOLC – Multi-hazard simulation and crisis response to a major low-probability volcanic eruption in Guadeloupe and Martinique

Context and objectives

La Soufrière in Guadeloupe and Mont Pelée in Martinique are among the most dangerous volcanoes in Europe, owing both to their eruptive potential and to the exposure of populations: nearly 640,000 people live within 30 km of these two edifices, both now placed on yellow alert after several years of non-eruptive unrest. With nineteen volcanoes active over the past 10,000 years and up to 1.5 million people living close to an active volcano across its territories, France is the third most exposed country in the world to volcanic threat.

Yet the territorial management of a major eruptive scenario presupposes having, beforehand, an objective and shared scientific representation of the multiple impacts of such an eruption. This representation is today sorely lacking for a "worst-case" HILP-type scenario (High Impact, Low Probability). These rare but devastating events largely elude the French crisis-response doctrine, formalised in the ORSEC plan (the national civil-protection emergency-response framework), which rests almost exclusively on the mass evacuation of threatened populations.

The IRIVOLC project intends to fill this gap by developing, beyond the state of the art, the science and the decision-support tools that crisis stakeholders need in order to confront a major HILP volcanic eruption. It is organised around three scientific challenges: simulating, at high resolution, the hazardous volcanic phenomena generated by a major explosive eruption (pyroclastic flows, flank collapses, associated tsunamis, ash dispersal); quantifying, in time and space, their multiple societal impacts and evacuation strategies, using agent-based models that incorporate human behaviour; and testing the effectiveness of crisis-response strategies in order to produce risk metrics and decision tools.

Structured into four work packages, IRIVOLC is fully embedded in the "data – models – decision" continuum at the heart of Axis 1 of the PEPR IRiMa. Above all, the project aims to support a paradigm shift in response doctrine: beyond evacuation alone, it seeks to recognise that a major eruption generates lasting impacts well beyond the directly threatened zone, and to prepare a complementary strategy of "living with" the risk, based on a business-continuity plan for the populations who will have to preserve their living conditions on the periphery of the danger zone.

The consortium brings together a broad set of researchers in geology, volcanology, mathematics and numerical modelling, physical and social geography, and political science. IRIVOLC draws on the volcanological observatories of Guadeloupe and Martinique, national monitoring infrastructures, and a long-standing collaboration with the operational actors of crisis management, in the overseas departments as well as in mainland France.