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Tuesday 20 November 2018

'Giant wave could badly damage Dublin and Cork' scientists warn

IT IS "quite possible" that Ireland could in future be hit by a tsunami or giant wave causing serious damage to low-lying cities like Cork, Galway, Limerick and Dublin, experts warnedyesterday.

Ireland had been hit by tsunamis twice in the last 300 years, according to Professor Mike Williams of NUI Galway. Professor Williams, of the Department of Earth and Ocean Sciences, said predicting tsunami was the same as looking at earthquake activity.

Ireland was affected by a tsunami generated by the Lisbon earthquake of 1755, he said. That tsunami took about three to four hours to reach the west coast of Ireland where it was reported to have destroyed the castle at Coranroe on the north coast of County Clare.

The waves affected Cork harbour, England and the Scilly Isles and also travelled the other way across the Atlantic causing waves as high as houses to strike the Caribbean Islands.

In 1860 another tsunami affected the Cork coast where the tide went out and several big waves came in.

In another incident, said Professor Williams, 15 people were swept off the Aran Islands on a calm day in 1852 apparently by atsunami.

While we were on a relatively stable plate we still suffered from earthquakes with one recorded over 20 years ago in the Menai strait off Wales. He explained that there are still active faults in the Bay of Biscay and an earthquake there would have some effect on Ireland.

There were also fears about the collapse of the Canary Islands or part of them. If they collapsed all at once, the resulting tsunami would cause serious damage toIreland's low-lying cities.

Such an event was not necessarily far in the future, Professor Williams warned.

He pointed out that such waves can be generated by earthquakes, by the collapse of submarine sediment, the collapse of oceanic volcanoes or some combination of these.

Asked what should be done to protect against a tsunami he said the cost had to be balanced against the likelihood of one tsunami hitting Galway Bay for example in the next 300 years.

Cork city already floods at high tide and that should be addressed, he added.

An expert on climate change, Dr John Sweeney of NUI Maynooth, said the more short-term risk to Ireland came from storm surge activity, along with sea levels predicted to rise half to one metre by the end of the century.

He pointed out that in February 2002 we exceeded the highest water levels of the 20th century in Dublin where Ringsend and other areas were flooded. While this usually happened once every 200 years recurrences could hit us morefrequently.

Dr Sweeney described as "bold and imaginative" a plan put forward by the Irish Academy of Engineering which proposed that a large dyke be built around Dublin Bay by 2050 to protect places such as Sutton, Clontarf, and Sandymount from rising sea levels as a result of global warming.

Another expert, Canadian geologist-geographer Edward Bryant said tsunamis had happened with greater frequency then modern science would like us to believe and no coastline was safe.

He had found signs of giant waves sweeping over 425 feet high headlands in southeast Australia, roaring down the US west coast and carving into the bedrock of the Scottish coastline north of Edinburgh.

Bryant, the head of geosciences at Woolongong University near Sydney, believed the famous St Andrews golf course was a tsunamideposit.

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