Tsunamis affecting the British Isles
Tsunamis affecting the British Isles are extremely uncommon, and there have only been two confirmed cases in recorded history. However, meteotsunamis are somewhat more common, especially on the southern coasts of England around the English and Bristol Channels.
- 1 Confirmed tsunamis
- 2 Possible tsunamis
- 3 Future tsunamis
- 4 See also
- 5 Notes
- 6 External links
Scotland (6100 BC)
The east coast of Scotland was struck by a 70 feet (21 m) high tsunami around 6100 BC, during the Mesolithic period. The wave was caused by the massive underwater Storegga slide off Norway, which occurred then. The tsunami even washed over some of the Shetland Islands. Tsunamite (the deposits left by a tsunami) dating from this event can be found at various locations around the coastal areas of Scotland, and are also a tourist feature in the Montrose Basin, where there is a layer of deposited sand about 0.6 metres (2.0 ft) thick.
At the time, what became the east coast of England was connected to the areas of Denmark and the Netherlands by a low-lying land bridge, now known to archaeologists as Doggerland. The area is believed to have had a coastline of lagoons, marshes, mudflats, and beaches, and may have been the richest hunting, fowling and fishing ground in Europe then available. Much of this land would have been inundated by the tsunami, with a catastrophic impact on the local human population.
Lisbon earthquake (1755)
The coast of Cornwall was hit by a three metre high tsunami on 1 November 1755, at around 14:00. The waves were caused by the 1755 Lisbon earthquake. The tsunami took almost four hours to reach the UK. The tsunami was also observed along the south coast of England and on the River Thames in London. Contemporary reports say that there were three of these tsunami waves, and that the sea receded very quickly, then rose up. At St Michael's Mount, the sea rose suddenly and then retired; ten minutes later, it rose 6 feet (1.8 m) very rapidly, then ebbed equally rapidly. The sea rose 8 feet (2.4 m) in Penzance and 10 feet (3.0 m) at Newlyn; the same effect was reported at St Ives and Hayle. Although there is no record of the overall death toll, the 19th century French writer, Arnold Boscowitz, claimed that "great loss of life and property occurred upon the coasts of Cornwall".
On 20 July 1929 a wave reported as being between 3.5 and 6 metres high struck the south coast including busy tourist beaches at Worthing, Brighton, Hastings and Folkestone. Two people drowned and the wave was attributed to a squall line travelling along the English Channel. 
South coast (2011)
A small tsunami with a peak wave height anomaly of 40 cm occurred on 29 June 2011 along the south coast of England. The tsunami was described as mild and there were no records of injuries or damage. Video footage clearly showed the tsunami and there were reports of fish leaping out the water and hair lifting up because of a static charge. Initial media speculation attributed the event to an underwater landslide, as no earthquakes were recorded at the time. However the British Geological Survey concluded that it was unlikely to have been caused by a submarine landslide and was probably a meteotsunami.
England and Wales (1014)
A widespread flood was reported in the Anglo-Saxon Chronicle to have occurred in western Britain, from the coast of Cumbria to Kent, on 28 September 1014. William of Malmesbury stated that "A tidal wave... grew to an astonishing size such as the memory of man cannot parallel, so as to submerge villages many miles inland and overwhelm and drown their inhabitants." The event was also mentioned in Welsh bardic chronicles.
Dover Straits earthquake(1580)
On 6 April 1580, a 5.8 magnitude earthquake occurred with its epicentre on the sea bed close to Calais. Giant waves were reported at the time and hundreds of people were killed when ships were sunk by the waves and the low-lying coastal land around Calais was inundated by the sea. In Dover, part of the chalk cliff collapsed, taking with it part of Dover Castle. A contemporary French account states “in the city of Calais such a horrible and terrible earthquake came to pass that a great part of the houses fell, and even the sea overflowed into the city and did ruin and drown a great number of houses, and numerous persons perished, and a great multitude of beasts lost which were at pasture outside this city.” In recent years, it has been suggested that these waves were a tsunami and not seiches. It is unlikely that the earthquake alone was strong enough to rupture the sea bed to trigger a tsunami, but it appears to have been sufficiently powerful to have caused an undersea landslide that was quite capable of generating a tsunami, as tragically happened in Papua New Guinea in 1998, killing around 2500 people.
Bristol Channel (1607)
The Bristol Channel floods, which occurred on the morning of January 30, 1607 (New style), are suggested to be a tsunami caused by an earthquake, a landslide from the Irish coast or a freak combination of high tides and a storm surge. There is historical evidence suggesting a tsunami, including eyewitness accounts describing a wave as "mighty hilles of water" - with sparks - and a wave that travelled so fast that not even a greyhound could escape it.
There is an ancient, large faultline off the Southwestern tip of Ireland, which scientists say could have possibly have triggered a tsunami in the Irish Sea. The continental shelf of Ireland is also very steep, with a drop of about 100 metres, and scientists believe the 1607 tsunami might have been triggered by a landslide here, if not an earthquake. Scientists and geologists say that after studying the disaster they are more convinced that it was a tsunami, rather than a simple storm surge.
North Sea (1858)
A tsunami was reported by witnesses in England, Germany, the Netherlands and Denmark on June 5, 1858. A witness stated that at 9.15 am the sea in Pegwell Bay, North Kent, "suddenly receded about 200 yards and returned to its former position within the space of about 20 minutes". The Times reported severe thunderstorms and flooding in the west of England on the same day. Due to the weather conditions it may have been a meteotsunami.
In the 1990s, geologists realised that the Cumbre Vieja volcano in La Palma, off North Africa in the Canary Islands could pose a tsunami risk to Britain, as it is seemingly unstable. They concluded that a future volcanic eruption will result in the mass of rock alongside the volcanoes breaking off and falling into the sea as a massive landslide. This in turn will generate a huge tsunami, which will surge into the Atlantic Ocean and hit Spain, Portugal, the east coast of the United States, France, and the south coast of England. It is estimated that the waves will take around 6 hours to reach England, and that when they do they will be around 10 metres (30 ft) high. Britain would be badly hit, and it is believed by some that if nothing is done, thousands of lives will be lost. However, there is considerable controversy about the accuracy of these predictions. Researchers at Delft University of Technology in the Netherlands found the island to be much more stable than was widely believed, estimating that it would take at least another 10,000 years for the island to grow enough for there to be a danger.
Another tsunami that geologists believe will hit Britain would be caused by a huge earthquake on a fault off the coast of Portugal; the same fault that caused the massive 1755 Lisbon earthquake (see above). Strain has been accumulating on that fault, which will eventually result in the fault breaking again, creating another megathrust earthquake, which could be as big as the 1755 earthquake (which was an estimated magnitude 9). When the earthquake happens, the south coast of England will most likely be affected by a tsunami, as it was in 1755. If it follows the same pattern as the 18th century quake, it will probably take around 4 hours for the tsunami to reach Cornwall.
- Haslett, Simon K; Mellor, Holly E.; Bryant, Edward A. (2009). "Meteo-tsunami hazard associated with summer thunderstorms in the United Kingdom". Physics and Chemistry of the Earth, Parts A/B/C 43 (17–18): 1016–1022. Bibcode:2009PCE....34.1016H. doi:10.1016/j.pce.2009.10.005. Retrieved 8 July 2011
- Haslett, Simon K; Bryant, Edward A. (2009). "Meteorological Tsunamis in Southern Britain: an Historical Review". The Geographical Review 99 (2): 146–163. doi:10.1111/j.1931-0846.2009.tb00424.x
- Patterson, W, "Coastal Catastrophe" (paleoclimate research document), University of Saskatchewan
- Vincent Gaffney, "Global Warming and the Lost European Country"
- Bernhard Weninger et al., The catastrophic final flooding of Doggerland by the Storegga Slide tsunami, Documenta Praehistorica XXXV, 2008
- Britain), Royal Society (Great; Hutton, Charles; Shaw, George; Pearson, Richard (1755). "An extraordinary and Surprising Agitation of the Waters, though without any perceptible Motion of the Earth, having been observed in various Parts of this Island, both Maritime and Inland, on the same Day, and chiefly about the Time that the more Violent Commotions of both Earth and Waters so extensively affected many very distant Parts of the Globe; the following Accounts, relating to the former, were transmitted to the Society; in which are specified the Times and Places when and where they happened". The Philosophical Transactions of the Royal Society XLIX: 647–653. Retrieved 5 July 2011.
- Boscowitz, Arnold (1890). Earthquakes. Routledge. p. 192. Retrieved 2008-10-18.
- "Meteotsunami | South West England | June 2011 | British Geological Survey (BGS)". bgs.ac.uk. 2011. Retrieved 8 July 2011.
- "BBC News - Underwater landslide likely cause of 'mild tsunami'". bbc.co.uk. 29 June 2011. Retrieved 30 June 2011.
- Stampf, Olaf, "Scientists Say North Sea Is Vulnerable to Tsunamis", Der Spiegel (English edition), 2012-04-14
- "Violent Thunder Storms", The Times, June 7, 1858, p.9
- Lean, Geoffrey (2 Jan 2005). "Britain could be hit by 30ft wave, says top scientist - Environment - The Independent". The Independent (London: INM). ISSN 0951-9467. OCLC 185201487. Retrieved 8 July 2011.
- "New research puts 'killer La Palma tsunami' at distant future". physorg.com. 20 September 2006. Retrieved 2008-10-18.
- "Tsunamis". National Maritime Museum. Retrieved 31 May 2013.
- "Tsunami theory of flood disaster: Bristol Channel". BBC NEWS. Retrieved 31 May 2013.
- "Tsunami waves wiped out prehistoric Scottish communities". New Scientist. 4 August 1990. Retrieved 31 May 2013.
- "Scientists warn of massive wave". CNN. 29 August 2001. Retrieved 31 May 2013.
- "Tidal wave threat 'over-hyped': Canary islands". BBC NEWS. 29 October 2004. Retrieved 31 May 2013.
- "2060: Tsunami horror hits Britain". Independent on Sunday. 5 November 2006. Retrieved 31 May 2013.
Historic tsunami in Britain since AD 1000: a review (Journal: Natural Hazards and Earth System Sciences (2008) 8, p.587–601)