Historic tsunami in Britain since AD 1000: a review

Abstract

Abstract. The British coast is not considered at particular risk from tsunami, a view that is supported by a number of recent government reports. However, these reports largely ignore some written historic records that suggest southern Britain has experienced a number of events over the past 1000 yrs. This study briefly assesses these records and recognises four groups of events: 1) sea disturbance and coastal floods in southeast England linked to earthquakes in the Dover Straits (e.g. 1382 and 1580), 2) far-field tsunami reaching the coast of the British Isles, for example, from earthquakes along the Azores-Gibraltar Fault Zone offshore Portugal (e.g. 1755), 3) tsunami associated with near-coastal low magnitude earthquakes (e.g. 1884 and 1892), and 4) a flood event in AD 1014 that has been linked to comet debris impact. The seismogenic events range from minor water disturbance, through seismic seiching, to small and "giant" waves, suggesting near-coastal, low-magnitude, shallow earthquakes may be capable of triggering disturbance in relatively shallow water, as supported by similar occurrences elsewhere, and that the British tsunami risk requires a more careful evaluation.

A wave-competence approach to distinguish between boulder and megaclast deposits due to storm waves versus tsunamis

“…Conversely, boulders at positions B-1 and B-C could have been pushed up the backshore scree slope by a tsunami or also be product of storm waves that over-topped the beach. Statigraphy, clast orientation, weathering, aging deposits and outcrops coupled with comparison to known storm or tsunami events are an important tools to use in deciphering causal mechanism (Dawson et al, 1996;Castle, 2000;Bryant and Nott, 2001;Scheffers, 2004;Williams and Hall, 2004;Whelan and Kelletat, 2005;Hall et al, 2006;Haslett and Bryant, 2008;Gutierrez-Mas et al, 2009a,b;Goto et al, 2010a,b;Paris et al, 2010) and may allow use of the scree slope deposits . This example illustrates some pitfalls in certain boulder position that could arise and in the case of boulders C-B, B-C and B-1 such additional information might help weigh the conclusion about causal mechanism one way or another.…”

“…Historic records also show that southern Britain has experienced a number of tsunami events over the past 1000 years with the worst disaster occurring on January 30, 1607. That suspected tsunami surged up the Bristol Channel in the United Kingdom, flooding more than 500 km 2 of lowland along 570 km of coast and killing 2000 people Haslett and Bryant, 2008). However, other experts have concluded that this natural disaster was caused by storm waves (Horsburgh and Horritt, 2006).…”

New study on the 1941 Gloria Fault earthquake and tsunami

“…Ponta Delgada tide station, in the Azores, recorded a maximum amplitude of 0.2 m. The Portuguese press reported tsunami observations close to Lisbon and the overtopping of shallow areas close to Oporto (Leixões) (see Baptista and Miranda (2009) for details). Haslett and Bryant (2008) described tsunami observations along the English Channel at Newlyn (Cornwall, United Kingdom) and Le Havre (France). Debrach (1946) and Rothé (1951) reported damage to the submarine cables Brest-Casablanca and Brest-Dakar.…”

Vulnerability of the Dover Strait to coseismic tsunami hazards: insights from numerical modelling

“…Deposits are elusive at least partly because the coastline on both sides of the Dover Strait erodes (or locally accretes) at rates of at least 1 m yr −1 , whether due to natural causes such as storm surges, high waves, strong winds (Corbau et al 1993; Vasseur & Héquette 2000; Aernouts & Héquette 2006; Chaverot et al 2008) or to intense changes in land use (Ruz et al 2005). Absence of evidence, however, is not evidence of absence, and in a comprehensive synthesis of anomalous sea disturbances around British shores, Haslett & Bryant (2008) have cross‐examined the detailed historical accounts available for both the UK and the continent. They concluded that the dismissal by DEFRA of some historical reporting by chroniclers of the time was misinformed and unjustified.…”

“…Reports for 1580 of large waves reaching Kent and northern France at similar times are supported by up to six independent French, English and Flemish sources (Melville et al . 1996; Haslett & Bryant 2008). Flooding was more severe in Calais and Boulogne, but with 120 fatalities or more in Dover, additional deaths in France, and a minimum of 165 sunken ships reported.…”