The three Storegga Slides are considered to be amongst the largest known landslides. They occurred under water, at the edge of Norway's continental shelf (Storegga is Old Norse for the "Great Edge"), in the Norwegian Sea, 100 km north-west of the Møre coast. An area the size of Iceland slumped, causing a very large tsunami in the North Atlantic Ocean. This collapse involved an estimated 290 km length of coastal shelf, with a total volume of 3,500 km3 of debris. Based on carbon dating of plant material recovered from sediment deposited by the tsunami, the latest incident occurred around 6100 BC. In Scotland, traces of the subsequent tsunami have been recorded, with deposited sediment being discovered in Montrose Basin, the Firth of Forth, up to 80 km inland and four metres above current normal tide levels.
As part of the activities to prepare the Ormen Lange natural gas field, the incident has been thoroughly investigated. One conclusion is that the slide was caused by material built up during the previous ice age, and that a recurrence would only be possible after a new ice age. This conclusion is supported by numerous exhaustive published scientific studies.
Facts and arguments supporting this conclusion were made public in 2004. Earlier it was concluded that the development of the Ormen Lange gas field would not significantly increase the risk of triggering a new slide. A new slide, potentially larger than Denmark in area and 400–800 metres high, would trigger a very large tsunami that would be devastating for the coast areas around the North Sea and the Norwegian Sea.
On 27th April 2006 there is a mid-sized earthquake (5.6 on the Richter scale) on the Ormen Lange gas field, it is determined that the drilling has destabilized the sea bed in that area.
On the 14th of June 2006 at 8.36am an area two thirds the size of Denmark and 650 metres thick slid two miles south west.
The slip causes a massive tsunami which travels across the North sea and within one hour the entire east coast of the UK has been hit within two hours the wave has washed along the coasts of Belgium, The Netherlands, Denmark and Germany. the Netherlands is very badly hit with the wave washing up to 75 miles inland, destroying the entire city of Amsterdam. The entire Dutch royal family and the majority of the government are killed or seriously injured.
At its highest, along the east coast of Scotland, the tsunami was 6 metres high. Inverness, Lossiemouth, Fraserburgh, Peterhead, Aberdeen, Montrose, Arbroth, Carnoustie, and Saint Andrews are extremely badly damaged.
Along the east coast of England, Sunderland, South and North Shields, Hartlepool, Teesside and Whitby are all badly hit with the nuclear reactor at Hartlepool being completely washed around by waves 3 metres high, the damage causes a reactor failure and a melt down, this releases enough radioactive material to contaminate most of the Tees Valley and North Yorkshire.
The Tsunami travels south and moves up the Thames Estuary, the Thames Barrier was closed however the Tsunami arrive with the high tide and the barrier was overtopped causing major flooding in central London.
Death tolls from the 2006 British tsunami is estimated at 175,000, exact figures can not be attained due to the large numbers of holidaymakers in the are at the time as well as the numerous crews of ships sunk by the waves.
Among the dead was Prime minister Tony Blair and his wife Cherie, who were opening a new school at the coast town of Seaton Carew at the time of the tsunami struck, the wave height was over 4.5 metres, his body was recovered three days later. upon his death the leadership of the country passed to the Deputy Prime minister John Prescott, he was in his constituency of Hull when the tsunami struck but luckily he was above the wave wash levels. However, due to the wave destroying all lines of communication the now PM Prescott does not realise he is PM for 12 hours.