Storegga: can be repeated the largest tsunami in the history of mankind?

About 8,000 years ago, a giant wave flooded the coast of the Shetland Islands and washed away everything in its path. Its height was 25 meters (the size of a 7-storey building), the speed reached 35 meters per second. In contrast, the Indian ocean tsunami in 2004, in those days there were no cameras that could fix the disaster, no Internet, spread the news around the world. Instead, the water had receded, leaving behind many traces on the coastal landscape, which was kept undisclosed eight millennia.

Today, geologists, paleontologists and archaeologists trying to reconstruct the events of those years and understand how likely such a disaster these days. Tsunami around 6200 BC era, was associated with climate change and sudden collapse of the continental shelf in Norway. Three huge landslide captured 290 km of coastline and replaced nearly 3,000 cubic miles of sediments.

According to Dr. Jon hill from Imperial College London, the impact of the disaster, dubbed Storegga, was felt far beyond Scotland. The resulting wave, not only flooded the Shetland Islands, but came to Greenland.

Sturegga

Storegga, became one of the biggest disasters of its kind in modern history and caused the greatest tsunami ever known to mankind. At the same time, the disaster was only a speck in the sequence of events and the rapid changes that marked the end of the last ice age that lasted from 110,000 to 12,000 years ago.

At the peak of glaciation a thick layer of ice covered modern Canada and the Northern United States, much of Asia, Russia, Northern Europe and the UK. About 20 000 years ago there has come warming. Its causes are still being debated, but there is plenty of evidence that by the end of the ice age brought seasonal changes of solar energy, which may have exacerbated the natural growth of greenhouse gases in the atmosphere.

When the ice began to melt, Britain turned from icy tundra to a forested area with a land bridge is a large piece of land called Doggerland, which connected the British Islands with Denmark and the Netherlands. This was an extremely attractive place for the life of the people of the Mesolithic, with its many lakes, estuaries, forests and salt marshes.

About 8,000 years ago, a giant wave flooded the coast of the Shetland Islands and washed away everything in its path. Its height was 25 meters (the size of a 7-storey building), the speed reached 35 meters per second. In contrast, the Indian ocean tsunami in 2004, in those days there were no cameras that could fix the disaster, no Internet, spread the news around the world. Instead, the water had receded, leaving behind many traces on the coastal landscape, which was kept undisclosed eight millennia.

Today, geologists, paleontologists and archaeologists trying to reconstruct the events of those years and understand how likely such a disaster these days. Tsunami around 6200 BC era, was associated with climate change and sudden collapse of the continental shelf in Norway. Three huge landslide captured 290 km of coastline and replaced nearly 3,000 cubic miles of sediments.

According to Dr. Jon hill from Imperial College London, the impact of the disaster, dubbed Storegga, was felt far beyond Scotland. The resulting wave, not only flooded the Shetland Islands, but came to Greenland.
Storegga

Yellow numbers: the height of the tsunami, Storegga

Storegga, became one of the biggest disasters of its kind in modern history and caused the greatest tsunami ever known to mankind. At the same time, the disaster was only a speck in the sequence of events and the rapid changes that marked the end of the last ice age that lasted from 110,000 to 12,000 years ago.

At the peak of glaciation a thick layer of ice covered modern Canada and the Northern United States, much of Asia, Russia, Northern Europe and the UK. About 20 000 years ago there has come warming. Its causes are still being debated, but there is plenty of evidence that by the end of the ice age brought seasonal changes of solar energy, which may have exacerbated the natural growth of greenhouse gases in the atmosphere.

When the ice began to melt, Britain turned from icy tundra to a forested area with a land bridge is a large piece of land called Doggerland, which connected the British Islands with Denmark and the Netherlands. This was an extremely attractive place for the life of the people of the Mesolithic, with its many lakes, estuaries, forests and salt marshes.
Shetland Islands

In this area the Shetland Islands tsunami height reached 12 meters

Melting ice had other consequences. In North America he created a huge lake the size of the Black sea, which holds thanks to the surrounding glaciers. About 8200 years ago the last ice melted, the lake has burst, causing severe flooding in the North Atlantic. Over the next 100 years, sea level on our planet increased by 2-4 meters. This factor, combined with a tsunami caused by landslides, Storegga, led to flooding of Doggerland, once and for all separating the Kingdom from the “mainland”.

So can a giant wave like the one that came to the Shetland Islands 8000 years ago, repeated in our day?

Dr sue Dawson of Dundee University is one of the main researchers, Storagge. In her opinion, a tsunami in Europe is a more common event than previously thought.

Storegga, was the chief of them, but there is evidence that in 1755 the great wave that destroyed Lisbon, rushed to the South-West of England, and in the 5000 and 1500 BC two localized tsunami hit the Shetland Islands. In addition, there are many historical documents mentioning waves, which could be a tsunami, but left no prints in the landscape.

During periods of intense climate change events such as Storegga, be the most likely. According to Dr. Jennifer Stanford of the National Oceanographic center of Southampton over the past 45 000 years, about 70 % of all landslides in Norway occurred in the period of intensive melting of the glaciers, that is, from 16,000 to 4,000 years ago. The most likely cause of the landslide becomes an overload of the continental shelf with growth of volumes of water from melting ice, although its role can play and the earthquake and the exit surface of methane.

“Warming ocean could lead to decomposition of gas hydrates in the ice that contain methane, and that, in turn, leads to a destabilization of the bottom sediments and increase in seismicity. The combination of all these factors causing submarine landslides that could be tsunamigenic”. Already in Greenland, an increase in the number of small tsunamis associated with the collapse of icebergs. Therefore, our task is to determine the frequency and timing of landslides, which can cause big wave,” says Stanford.

“If in our days, an event that resembles Storage, send waves from Svalbard or Greenland towards the UK, its impact is truly catastrophic,” – says the researcher. “We can see the tsunami up to 10 meters, which completely flooded the cities of Edinburgh and Newcastle. At the moment the chances of such a massive natural disaster are quite small, but the tsunami of smaller size is quite probable.

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