A catalogue of tsunamis reported in the UK

Summary Over the years many events around the coasts of the UK have been described as tsunamis or tidal waves. Evaluation of the data indicates only a few of these events are definitely tsunamis. The data types vary from sedimentary deposits, primarily of pre-historic events, through recorded observations, particularly reports in 19th and 20th century newspapers, to tide gauge records mainly from the latter half of the 20th century. The major tsunami events within the UK include the Storegga tsunami which struck coasts in the northern half of the country about 8150BP, and the tsunami triggered by the 1755 Lisbon earthquake. Lesser events are primarily associated with earthquakes with epicentres offshore Portugal, but others are local events triggered by coastal cliff falls. These lesser events are often only noted on tide gauge records. Most reported events are probably not tsunamis. Many are likely to have been weather related events known as meteotsunamis. These are large amplitude, long wavelength seiches caused by rapid changes in air pressure. They occur predominantly along on the south coast of England and have over the years caused fatalities and damage to structures. Some are uncertain events where the triggering mechanism is not clear. These include sediment layers found in Shetland resembling tsunami deposits but it is uncertain if the sediment is deposited by waves or are aeolian or through downslope processes.