Tsunamis may have hit Kerry coast


THE POSSIBILITY that the south Kerry coast has over the centuries been struck by long tsunami waves of over 50ft in events that have lived on in folk memory has been raised by an archaeologist.

Cross-checking folk tales with archaeological and geological evidence, Alan R Hayden, director of more than 200 medieval excavations since 1987 in Ireland, said the grouping of Valentia, Beginish and Church islands may bear the scars of earthquakes and tsunami-type waves in medieval times.

His research is reported in the current edition of the Journal of the Kerry Archaeological and Historical Society.

Damage to the south and southwest surrounding walls of Church Island, an important early medieval ecclesiastical site, was unlikely to have been caused by a storm or heavy swell, he concluded.

Instead, the disappearance of the dry-stone wall at the south of Church Island could be due to the much longer wavelength of a tsunami, probably coming from an earthquake in the southwest.

There are indications that Church Island may have been connected to Beginish Island but that the wave led to erosion of the connecting land. A sand bar still partly connects the two islands.

The island became home to a monastic settlement in the seventh century but before that it was a centre for fuel for iron smelting.

A folk tale collected by a teacher in the early part of the last century offers an explanation for local place names connected to a road that ran from Dolus Head through the islands to Skellig.

The road, a pre-medieval structure, is called Bóthar na Scairte, or road of the cataclysm, and it is traceable for some distance on Valentia. In the folk tale the road and a local hero were destroyed by a great cataclysm, probably an earthquake followed by a wave.

According to the tale, “a terrible wave 50ft high” rushed towards a gathering of people on a summer day on Valentia. Everyone except the hero scrambled to higher ground. The wave separated Skellig and Valentia from each other.

According to Mr Hayden, the occurrence of tsunamis affecting the south and west coasts of Ireland is surprisingly well documented. The 1775 Lisbon earthquake caused a tsunami which reached Kinsale and which flooded the Spanish Arch in Galway, for example.

In the 1850s a tidal wave washed 15 men off the cliffs of Inishmore, he noted.

“The British Geological Survey has suggested that earthquakes on a known unstable fault that lies off the southwest coast of Ireland may have caused some of these tsunamis,” Mr Hayden wrote.