UNESCO: Meter-High Mediterranean Tsunami Wave 'Close to 100%' Likely Within 30 Years

On June 22, 2022, the United Nations Educational, Scientific and Cultural Organization (UNESCO) warned that the probability of a tsunami wave exceeding 1 meter somewhere in the Mediterranean within the next 30 years, roughly through 2052, is close to 100%. UNESCO stressed this is not a prediction of an imminent disaster, a guarantee that France's Riviera specifically would be struck, or a forecast that every part of the Mediterranean would see identical waves.

The basin has the ingredients for dangerous tsunamis: earthquakes along active faults in the Ligurian Sea near the French and Italian coasts, further quakes where the African and Eurasian tectonic plates meet off North Africa, and underwater landslides that can trigger more localized waves. Researchers describe the Mediterranean as having the largest historical tsunami record after the Pacific; along the French Riviera alone, roughly 20 tsunami events have been reported between the 16th century and the early 2000s, some with waves exceeding two meters.

Timing compounds the risk. In some local scenarios on the Riviera, the first waves could reach shore in under 10 minutes, while France's national tsunami warning center, Cenalt, running since July 2012, is designed to send its first alert to emergency authorities within 15 minutes of a dangerous earthquake. That leaves little room for a public warning to reach the beach in time, which is why researchers and officials around Nice are mapping walking routes and refuge sites so residents know when to leave the coast immediately.

Past events show the danger is real. On October 16, 1979, the collapse of a Nice port construction site triggered a landslide and tsunami that killed eight people, with water reaching 3.5 meters locally and flooding 150 meters inland, a reconstruction in the journal Natural Hazards found. Worldwide, tsunamis have killed more than 250,000 people since 1970, a toll dominated by the 2004 Indian Ocean disaster and the 2011 tsunami in Japan.