A tsunami that would affect our shores could come from two possible places.
There is the possibility that the build up of sedimentary materials along the continental shelf of the Eurasian plate could be disturbed with earthquake activity and trigger a massive tidal wave. A large enough earthquake along the spreading constructive boundary of the mid-Atlantic Ridge could do this. Professor Williams of NUI Galway states that Ireland is on a relatively stable plate; however, there are still active faults in the Bay of Biscay and in Iceland which could trigger a tsunami and devastate Ireland. Events such as the earthquake recorded off the Menai strait off Wales 20 years ago, and the more recent quake recorded off Wicklow, are relatively rare and the possibility of a tsunami being generated through these means in the near future is not very significant.
A tsunami that is more likely to affect Ireland will come from the Canaries, scientists tell us.
Research based on collaboration between Dr. Simon Day of Benfield Greig Hazard Research centre at University College London
and Dr. Steven Ward of the University of California relates to the possible effects of the future eruption of the Cumbre Vieja volcano on the Canary Islands. A block of rock twice the volume of the Isle of Man could break off
the island following an eruption, and would fall into water about 4 miles deep at 350 km/hr. There would be a debris avalanche extending 60km from the Island. According to the research of these two men the energy released by such a collapse would be equal to the entire U.S energy consumption for 6 months. Waves would be expected to reach the UK and Ireland after 6 hours.
The possible effects of such an avalanche is discussed elsewhere; whether or not such an event is likely to occur in the short of long term, or even at all is the focus of this section
EVIDENCE FOR…
+ A UK report assessing the risk of tsunamis, following the Boxing Day tsunami in S.E Asia, concluded that the risk is low, but not to be completely discounted. The British Geological Survey report, (which included contributions from Proudman Oceanographic Laboratories, specialist consultants H. R. Wallingford and the MET office), found that existing defences may be sufficient, such as the Thames barrier and most other coastal walls and defences, but that there was always room for improvement.
+ According to D. Long and R. Holmes in their research focussing on Scotland and tsunamis thousands of years ago, they state that ‘The frequency of tsunamis can be considered extremely low but not non-existent and needs to be considered in the long-term planning for Scotland.’
+ British organisations such as DEFRA (Department for environment, food and rural affairs) have told the BBC that they believe action needs to be taken to help minimise the possible damaging effect a tsunami could have on the UK.
EVIDENCE AGAINST…
- Nobody can say when the volcano may erupt again and trigger the landslide. Some scientists believe that it may take 5 or 10 more eruptions to cause the collapse.
- Dr. John Sweeney from NUI Maynooth believes that the more short term risk to Ireland comes from the threat of storm surge activity, aswell as rising sea-levels, and not tsunamis.
