La Soufrière de Guadeloupe

The seismic and fumarollic activity of La Soufrière de Gaudeloupe increased in 1992. Continuing unrest led the Observatoire volocanologique et sismologique of Guadeloupe (OVSG-IPGP) to recommend in July 1999 to the authorities that the volcano alert be set to “Vigilance” (yellow). The OVSG-IPGP has been particularly vigilant and reinforced its monitoring following another significant increase of unrest in 2017 that culminated in magnitude 4.1 felt earthquake and a probable failed phreatic eruption on 28 april 2018. Volcanic activity remains difficult to forecast precisely, so the only way to stay safe, in case of an impending eruption, is to move away from the threatened area. This can be a major problem for the authorities and the population. In the French overseas departments, despite the presence of several volcanoes, there is limited experience in managing volcanic emergencies, especially in areas with a high population density and strategic assets, such as the Basse-Terre region of Guadeloupe in the Lesser Antilles. A mass evacuation is a complex process, involving many different actors who have to make decisions with limited information and high uncertainty, on short time scales. And the success of an evacuation will be dependent on the entire public authorities’ strategy and the public perception of volcanic risk. Furthermore volcanic hazards are characterized by a high degree of uncertainty regarding the type, intensity, and timing of eruptions. Emergency management must therefore take this into account. Therefore, it is crucial to devise and assess an emergency management strategy to identify potential problems and dangers that may arise during a mass evacuation. Crisis exercises can be planned to prepare the authorities and the population, but they are rarely carried out due to the human and resource costs involved. A series of evacuation scenarios are evaluated through simulations. In this context, agent-based models (ABMs) are particularly well-suited to simulate and model the complexity of mass evacuations (realism of agent behavior and environment, interaction between agents, observation of system dynamics at different scales, etc.). A series of evacuation scenarios is tested in order to provide recommendations and relevant information for stakeholders to assist them in the implementation of mitigation responses. The various scenarios highlight the diversity of challenges of a mass evacuation during a crisis of La Soufrière, and provide some valuable insights. Five scenarios attempt to answer various research questions related to mass evacuations. The scenarios suggest that effective evacuation risk management requires rigorous planning and an ability to adapt to evolving eruptive events.