A tsunami of biblical scale could be about to wipe us all out.
Scientists have discovered that a 1,000ft wave swept across the Earth some 73,000 years ago. The event was caused by the sudden collapse of Fogo volcano on the Cape Verde Islands, long before there were any coastal cities that might have been flattened. But some experts fear a similar giant collapse could present a real threat today, especially around volcanic islands.
Lead scientist Dr Ricardo Ramalho, from Columbia University in New York, said: “Our point is that flank collapses can happen extremely fast and catastrophically, and therefore are capable of triggering giant tsunamis. They probably don’t happen very often. But we need to take this into account when we think about the hazard potential of these kinds of volcanic features.”
Fogo volcano is one of the world’s largest and most active island volcanoes, erupting around every 20 years. Scientists have long known it had collapsed in the past, but whether this was gradual or sudden, or what caused it remained unknown.
Scientists from Columbia University’s Lamont-Doherty Earth Observatory have now provided evidence that the collapse was indeed sudden and catastrophic, producing a massive tsunami that had enough energy to carry huge boulders 2,000ft inland and nearly 650ft above sea level. Publishing their findings in the journal Science Advances, researchers used these unusual boulders as the basis for their study.
Lead author Ricardo Ramalho told said: “The first time I saw the boulders was back in 2007. At the time I was really puzzled by their origin, but I would never have guessed where they were from.”
In 2011, some French scientists published work about tsunami deposits on Santiago at sea level – which made him start thinking that these other boulders could be related. Ramalho said: “After a few days of mapping, I had found more than 40 boulders and that’s when I started to realise it was something big.”