A gigantic 800-foot wave slammed into the Cape Verde Islands 73,000 years ago with incredible force, throwing gigantic boulders at heights above the highest point of the Eiffel Tower.
This “mega tsunami” has been detailed in a new study published in the journal Science Advances, and it describes an absolutely massive wave off the coast of Africa that was created by a gigantic piece of the volcanic island of Fogo collapsing into the seat, sending tremendous volumes of rock into the water and creating a super-wave that was 300 feet high to start, and then blasted even higher into the sky when it collide with the island of Santiago near by, according to a Washington Post report.
The wave went flying across the ocean, quickly covering the 30 miles between the two islands before it smashed into Santiago, flying upward over a 600-foot cliff and eventually reaching 800 or possible 900 feet above sea level — higher than the Eiffel Tower — before finally subsiding. Scientists believe this huge wave sent gigantic boulders all the way to the top of the island, where they can be found today.
In fact, it was these huge boulders on this high plateau that caught the eye of Ricard Ramalho, who led the study out of Lamont-Doherty Earth Observatory at Columbia University. It seemed strange to him when he first noticed them in 2007 that they were so high above sea level, and so he began to look into it. He and a team of researchers in the years since have since discovered evidence that seems to suggest a mega tsunami was responsible.
Starting with the strange occurrence of massive boulders on top of an island off the coast of Africa, they tried to figure out how it got there. A tsunami seemed like a possible answer, but most tsunamis affect areas of low elevation, not way up hundreds of feet above sea level. So they took a look at nearby islands and especially Fogo, which today is an active volcano that stretches four miles off the sea floor.
They found evidence that there was a partial collapse of this island some 73,000 years ago, and there was evidence that a giant avalanche of rock could have produced a mega tsunami.
Not all scientists accept this explanation. Many argue that mega tsunamis are probably impossible as partial collapses aren’t sudden, they happen piecemeal. They think that although Fogo had certainly collapsed, it wouldn’t have happened all at once.
However, Ramalho thought the evidence suggested that a mega tsunami was the only reasonable explanation, and the evidence he and his team collected convinced him that this was indeed the culprit and the only possible force that could have carried such tremendously large rocks to the very top of an island.
To prove this, he used cosmogenic techniques to date the rock by measuring how long the sun’s rays had been shining on the boulder, and was able to date it back to around the time of the Fogo collapse.
To Ramahlo, it makes sense that volcanoes would be the cause of a mega tsunami, as they are created quite suddenly, with the Earth beneath suddenly driving up large columns of rock, and this instability can result in a sudden collapse, especially in the case of active volcanoes.
Some believe a similar thing happened in the Hawaiian islands 100,000 years ago. And there’s a possibility it could happen to us today, although perhaps it’s a remote possibility — still, some have suggested that the Cumbra Vieja volcano on the Canary Islands is a prime candidate for collapse and a subsequent mega tsunami that could blast across the ocean and strike the United States.
Tsunamis can be caused by either volcanoes or by earthquakes. They are a series of waves that happens when there is a sudden displacement of a large volume of water. They don’t resemble typical breaking waves, because their wavelength is much longer. Instead, they tend to resemble a sudden rising tide, which is why they are often called tidal waves even though they have no relation to tides.
Tsunamis are usually a problem for just the very edges of coastal areas, but they can cause tremendous devastation, and have done exactly that in recent years. The 2004 Indian Ocean earthquake and resulting tsunami killed tens of thousands of people in Southeast Asia and created a huge humanitarian crisis. The 2011 Japanese earthquake also caused a major tsunami that flooded large portions of the island and even caused the partial meltdown of a nuclear reactor at a power plant.