A catastrophic collapse of the Cumbre Vieja volcano on Spain's Canary Islands could trigger a 'megatsunami' that reaches the U.S. East Coast in a matter of hours, according to volcanologist Professor Bill McGuire.
McGuire's worst-case computer modeling, outlined in a BBC Science Focus article, suggests that if a massive section of the volcano's western flank breaks away and falls into the Atlantic Ocean, it could generate waves up to 65 feet high. These waves could reach Florida approximately nine hours after the collapse. Other estimates suggest waves reaching the U.S. East Coast could be around 33 feet high.
A flank collapse generates a tsunami by suddenly displacing a huge volume of water. McGuire noted that a volcano does not need to be actively erupting for a flank collapse to occur; gases seeping through the rock can weaken its structure, leading to a landslide.
He pointed to the volcano's steep western flank, which showed signs of partial detachment during a 1949 eruption. McGuire's research team confirmed in the 1990s that this large mass of rock was slowly moving towards the sea. He anticipates that this section will eventually crash into the Atlantic, initiating a megatsunami.
McGuire also cited evidence of prehistoric megatsunamis around the Canary Islands, with tsunami debris found nearly 980 feet above sea level, indicating at least five such events in the past million years. While the exact scale of future destruction remains debated among scientists, McGuire's model highlights the potential catastrophic consequences for the U.S. East Coast.
Historical events like the 1792 Unzen volcano landslide in Japan, which killed around 15,000 people, and the 2018 Anak Krakatau volcano collapse in Indonesia, which caused a tsunami that killed over 400 people, illustrate the destructive potential of such volcanic events. These incidents demonstrate that volcanic tsunamis can manifest as a series of powerful waves, causing repeated flooding.