Tsunami intensity scale based on wave amplitude and current applied to the French Riviera: the case study of local seismicity

The French–Italian Riviera faces several geophysical hazards, including recurrent earthquakes and underwater landslides that can be tsunamigenic. The stakes are high since this is a densely populated and touristic area. Several studies have already been carried out, in particular to map tsunami hazard resulting from the near-field seismicity of the North Ligurian Faults System, which is located a short distance off the coast. In our most recent study, runup maps were developed together with local analyses of tsunami-induced current fields. However, no conclusions were drawn, based on these results, as of the associated tsunami risk along the coast. Here, to this effect, we apply a recently proposed tsunami intensity scale to the simulation results obtained in our previous work (maximum values of tsunami depths and currents). This intensity scale (7 levels) is mapped over the entire coastal area, and its site-specific values are discussed. The scale allows quantifying the potential damage inland and at sea, based on a standard coastal vulnerability that has been assessed through different records. It thus represents a useful tool to help improving our preparedness to tsunami hazard.