Advertise On EU-Digest

Anual Advertising Rates

10/24/15

Canary Isleands: 800-foot megatsunami happened 73000 years ago! Can it happen again?

Researchers at Columbia University have unearthed evidence of a massive 800-foot megatsunami, which they say occurred due to sudden collapse of Fogo volcano. The volcano is one of the world’s largest and most active island volcanoes. Current it towers 2,829 meters (9,300 feet) above sea level, and erupts about every 20 years, most recently last fall.

Researchers claim that the scale of the waves generated by this tsunami were above anything that has been ever witnessed or recorded in human history and their findings shed light on what lies in store for us if there are similar catastrophic collapse in the oceans.

In a 2011 study, French researchers looked at the Fogo collapse, suggesting that it took place somewhere between 124,000-65,000 years ago; but that study says it involved more than one landslide. The French researchers estimate that the resulting multiple waves would have reached only 45 feet–even at that, enough to do plenty of harm today.

The new study adds a new possible example; it says the estimated 160 cubic kilometers (40 cubic miles) of rock that Fogo lost during the collapse was dropped all at once, resulting in the 800-foot wave. Santiago Island lies 55 kilometers (34 miles) from Fogo.

In the early 2000s, other researchers started publishing evidence that the Cape Verdes could generate large tsunamis. Others have argued that Spain’s Canary Islands have already done so. Simon Day, a senior researcher at University College London has sparked repeated controversy by warning that any future eruption of the Canary Islands’ active Cumbre Vieja volcano could set off a flank collapse that might form an initial wave 3,000 feet high. This, he says, could erase more than nearby islands.

Such a wave might still be 300 feet high when it reached west Africa an hour or so later he says, and would still be 150 feet high along the coasts of North and South America. So far, such studies have raised mainly tsunamis of publicity, and vigorous objections from other scientists that such events are improbable. A 2013 study of deep-sea sediments by the United Kingdom’s National Oceanography Centre suggests that the Canaries have probably mostly seen gradual collapses.

Part of the controversy hangs not only on the physics of the collapses themselves, but on how efficiently resulting waves could travel. In 1792, part of Japan’s Mount Unzen collapsed, hitting a series of nearby bays with waves as high as 300 feet, and killing some 15,000 people. On July 9, 1958, an earthquake shook 90 million tons of rock into Alaska’s isolated Lituya Bay; this created an astounding 1,724-foot-high wave, the largest ever recorded. Two fishermen who happened to be in their boat that day were carried clear over a nearby forest; miraculously, they survived.

The 2004 Indian Ocean earthquake and tsunami killed 230,000 people in 14 countries; the 2011 Tohoku event killed nearly 20,000 in Japan, and has caused a long-term nuclear disaster.

When Fogo erupted last year, Ramalho and other geologists rushed in to observe. Lava flows (since calmed down) displaced some 1,200 people, and destroyed buildings including a new volcano visitors’ center. “Right now, people in Cape Verde have a lot more to worry about, like rebuilding their livelihoods after the last eruption,” said Ramalho. “But Fogo may collapse again one day, so we need to be vigilant.”

Read more: 800-foot megatsunami happened 73000 years ago! Can it happen again? - Techie News

No comments: