EGU23-7342, updated on 25 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Risk communication during seismo-volcanic crises: the example of Mayotte, France

Robin Lacassin1, Maud Devès1,2, Hugues Pécout3, and Geoffrey Robert1
Robin Lacassin et al.
  • 1Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France (
  • 2Université Paris Cité, Centre de recherche psychanalyse médecine et société, CNRS, Paris, France (
  • 3Université Paris Cité, Collège international des sciences territoriales, CNRS, Paris, France

Population information is a fundamental issue for effective disaster risk reduction. As demonstrated by numerous past and present crises, implementing an effective communication strategy is, however, not a trivial matter. Here, and in Devès et al. 2022, we draw lessons from the seismo-volcanic “crisis” that began in the French overseas department of Mayotte in May 2018, and which is related to a submarine eruption off the eastern coast of the island. The seismo-volcanic activity is still ongoing today and large uncertainties remain about its possible future evolution. Mayotte’s case study is interesting for several reasons: (1) although the seismo-volcanic phenomenon itself is associated with moderate impacts, it triggered a social crisis that risk managers themselves qualified as “a communication crisis”, (2) risks are perceived mostly indirectly by the population, which poses specific challenges, in particular to scientists who are placed at the heart of the risk communication process, and (3) no emergency planning or monitoring had ever been done in the department of Mayotte with respect to volcanic issues before May 2018, which means that the framing of monitoring and risk management, as well as the strategies adopted to share information with the public, has evolved significantly over time. Our first contribution is to document the gradual organization of the official response. Then we attempt to understand what may have led to the reported “communication crisis”. To that end, we collect and analyze the written information delivered by the main actors of monitoring and risk management to the public from May 2018 to April 2021. Finally, we compare its volume, timing, and content with what is known of at-risk populations’ information needs. Our results outline the importance of ensuring that communication is not overly technical, that it aims to inform rather than reassure, that it focuses on risk and not only on hazard, and that it provides clues to possible risk scenarios. We issue recommendations for improvement of public information about risks in Mayotte, but also elsewhere in contexts where comparable geo-crises may happen. 

Devès, M., Lacassin, R., Pécout, H., & Robert, G. (2022). Risk communication during seismo-volcanic crises: the example of Mayotte, France. Nat. Hazards Earth Syst. Sci., 22, 2001–2029,

How to cite: Lacassin, R., Devès, M., Pécout, H., and Robert, G.: Risk communication during seismo-volcanic crises: the example of Mayotte, France, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7342,, 2023.