Tsunami Risk and Alert Perceptions in Five Municipalities bordering the French Mediterranean Basin

Abstract. Since the major tsunami that occurred in 2004, many studies have dealt with the evacuations, hazard mapping and awareness-actions, rather than on the perceived tsunami risk nor on alert perceptions declared locally by the population. In this study, we analyzed a sample of 750 answers to a face-to-face questionnaire, gathered from residents or workers in 5 densely-urbanized municipalities (e.g., Bandol, Bastia, Cannes, Six-Fours-Les-Plages, Sanary-sur-Mer), likely to be hit by a tsunami and bordering the French Mediterranean basin. Results first confirmed the tendency to underestimate the tsunami risk, as only 15.6 % identify tsunami as a risk. However, 48.7 % declare they should take protective actions if they feel ground-shaking on the seafront, and even 65.3 % if they also see a anormal sea movement. In contrast, the efficacy of alerting tools and the actors who can alert them are overestimated, as 44.7 % of the respondents think they should be alerted by sirens and 11.7 % by SMS, while such tools are not systematically present and rarely cover tsunami evacuation zones. And only 29.4 % correctly identify the official alert senders: mayors or prefectures. In contrast, 55.7 % declare they go high ground if they receive such instructions in one Alert SMS. The age, gender, residency status or location of the respondents explain a few differences in the collected data. However, relationships between tsunami risk and alert perceptions appear statistically not corelated. All the knowledge produced in this study finally might help the municipalities further develop awareness-actions and information on the tsunami, and inform what strategy they may apply in a short future to better increase the tsunami preparedness.