After the catastrophic tsunami on 26 December 2004 in Southeast Asia that caused around three hundred thousand human lives, the question whether or not such a flood wave is possible in the North Sea is once again current news. The presence of an unusual layer of sand, several centimeters to decimeters thick found in the sedimentation along the Scottish east coast and in North England, is evidence that a tsunami took place here 7900 years ago. Its influence is also apparent in Iceland, Norway, the Faroe Islands and the Shetland Islands. Studies have shown that an underwater slide of the ocean bottom near Norway had caused the so-called Storegga Tsunami, which must have reached a wave height of 25 meters near the Shetland Islands.
Other tsunamis in the North Sea include the one from 6 April 1580, when an underwater earthquake flooded the city and vicinity of Calais. A second tsunami followed the next day, reaching Mont St. Michel in Normandy. The inhabitants survived a wave height of more than 15 meters. An earthquake caused a tsunami near the Doggers Bank in 1931, affecting primarily Great Britain.
The Netherlands and Belgium will probably never have any problems from a tsunami, because by the time the wave reaches this coast, the relatively shallow souterhn North Sea will have strongly subdued it. Tsunamis in the North Sea could be caused by the continental slope shifting between North England and Norway and by the collapse of a part of the Cumbre Vieja volcano on La Palma (Canary Islands). Belgium scientists think that this could cause a wave with a height of no more than 1.5 to 2 meters by the Belgium and Dutch coasts.
