“It is not a question of if, but when,” recall seismologists.
What if the next big wave did not come from the Pacific, but from the Atlantic? Under calm waters, a gigantic geological flaw could one day cause a devastating event, capable of hitting the European coasts. Geologists nicknamed it the “flaw in the Azores-Gibraltar fracture zone”. It extends over several hundred kilometers under the Atlantic Ocean, between the African and Eurasian tectonic plates.
A Franco-Portuguese team has shown that this fault located near the city of Cadiz, Spain, always moves and accumulates energy. It could ultimately cause an earthquake equivalent to that of the 18th century. “”It is a tectonic delay bomb “summarizes a geophysicist in Nature Communications Earth & Environment. And unlike the Pacific Fire belt (where 90% of earthquakes take place and 95% of terrestrial volcanic eruptions in the world), the North Atlantic is less monitored, because historically much calmer.
In this region, the underground movements are slow, but powerful. According to several studies, this flaw could generate an underwater “mega-seism”, followed by a major tidal wave, like the one who had struck Lisbon in 1755. The dreaded scenario is precisely an underwater earthquake of magnitude 8 or more which would raise a huge column of water. The waves could reach the coasts of Portugal, Spain, even from the southwest of France in a few tens of minutes. Experts talk about a “low risk, but not zero“The problem is that this type of earthquake is rare, but unpredictable. And the coastal areas are not all prepared for a tsunami from the Atlantic.
Lisbon, Cadiz and other coastal cities strengthen their alert systems and provide evacuation plans. In France, the subject is still little publicized. However, according to UNESCO, tsunamis are increasingly frequent and deadly, especially because of the urbanization of coastal areas and climate change which complicates the forecast of impacts. “”It is not a question of if, but when“, Recall certain seismologists. The earth, even invisible under the ocean, therefore did not say its last word …
