May 23, 1847 Tsunami: Cornwall, England, United Kingdom

Cornwall 1847. On the 23 May 1847, there was a 0.9m to 1.5m rise and fall observed all day at Mounts Bay. One cause could have been the slight tremor that was felt at the Scilly Isles, Penzance and Mounts Bay. Edmonds (1862) reports nearby thunderstorms, but also the occurrence of an earthquake in Scilly and Cornwall. The cause of this tsunami is uncertain, so it could possibly be a meteotsunami or an earthquake tsunami. (reference #14269)

1847 May 23. Edmonds (1869) noted that in Mount’s Bay rises and falls of 3 to 5 feet (0.9-1.5m) occurred all day and similar effects at Plymouth in the evening. This has been linked with reports of a slight tremor felt in the Scilly Isles, Penzance and Mount’s Bay in the night before. Musson (1989) suggested that a large offshore earthquake occurred and the abnormal waves are associated with it. However locating an epicentre for the earthquake is not possible, nor is determining how such an earthquake induced the size of the tsunami wave reported. Also it is difficult to explain the time delay for a wave reaching west Cornwall and Plymouth in the evening to have come from come from an earthquake close enough to west Cornwall to be felt the night before […] information on the weather conditions suggests the events resemble meteotsunamis that have been reported previously on this coast […] This event is considered a non-tsunami event and is probably a meteotsunami. (reference #14326)

tsunami appears to have come ashore in Mount’s Bay on Sunday 23 May 1847, however, this time it is likely to be associated with a relatively high magnitude earthquake felt at the time in the Scilly Isles (Musson, 1989). DEFRA (2005) and Long and Wilson (2007) mention this event with reference to a later recounting of the event by Edmonds (1869) and state that the waves were up to 1.5m high, although Long and Wilson (2007) classify this event as “an uncertain tsunami event”. (reference #14215)