The Mediterranean may seem far removed from the world’s major tsunami zones, but history and modern modeling show that destructive waves can strike the French Riviera with surprisingly little warning. Some tsunamis could reach shore in under 10 minutes, while past events have produced waves around two meters high, powerful currents, damage, and deaths.
The Montpellier researchers describe the Mediterranean as having the largest historical tsunami record after the Pacific. Along the French Riviera, they cite roughly 20 reported events between the 16th century and the early 2000s, including waves exceeding two meters. Several episodes show how differently the danger can unfold.
On February 23, 1887, an earthquake in the Ligurian Sea, with an estimated magnitude between 6.5 and 6.8, triggered a tsunami along the coast. Historical accounts describe the sea falling by about one meter in Antibes and Cannes, leaving fishing boats stranded. Waves approaching two meters then swept over the beaches.
A very different event occurred on October 16, 1979. Part of the construction site for a new commercial port in Nice (Alpes-Maritimes), beside the airport, collapsed into the sea. The resulting landslide and tsunami caused eight deaths, according to a reconstruction published in Natural Hazards. Effects were reported in Nice, Antibes, and Cannes, with disturbances observed in Antibes for about half an hour. The later study found that water reached elevations of 3.5 meters locally and flooded as far as 150 meters inland.
The May 21, 2003, Boumerdès earthquake (Algeria) demonstrated that the trigger could also lie across the Mediterranean. Its effects reached the Riviera about 75 minutes later. Investigators documented abrupt sea level drops (from 50 cm to 1.5 m), partially emptied harbor basins, swirling water, strong currents, and damaged boats in eight marinas. Harbor resonance, in which the shape of a basin reinforces the water's oscillations, helped explain why neighboring ports experienced different effects.
[...]