Rise in landslides linked to climate change


IRELAND AND much of northern Europe is seeing an increasing number of landslides, coinciding with more extreme weather patterns, according to the Geological Survey of Ireland (GSI).

Ireland had previously been considered a relatively benign environment as far as landslides were concerned.

But following the landslides in Derrybrien in Co Galway and Pollatomish, Co Mayo, in 2003, the Irish Landslides Working Group was set up to map areas prone to landslides and spot potential damage that can occur as a result of such activity.

The working group, which comprises members of the GSI, other Government agencies and the universities, is engaged in compiling a "planning tool" that may be used by local authorities and developers to pinpoint vulnerable areas where damage may occur.

According to the director of the GSI, Peadar McArdle, landslides were previously explained by long dry spells that could cause hillside bogs to crack. Once rain comes down heavily the dry bog just slips away.

"But we can't say that this year," Mr McArdle said yesterday. "It is now more likely it is heavy rain causing mobility between a layer of rock and bog above it," he added.

The principal geologist with the GSI and member of the working group, Koen Verbruggen, said pilot projects carried out in Sligo have shown there were many more landslides in the past than was previously recognised.

He points to the Geevagh, Co Sligo, area, where last week locals said the mountain "just slid down, the river burst its banks and flowed diagonally across the pitch and the damage has been devastating". Mr Verbruggen said testing had revealed several levels of peat in the ground, a feature that indicated the immediate area was prone to bogslides.

Among the studies currently under way is one along the east coast, where population levels indicate significant damage may occur if a landslide takes place.

The key to assessing the potential for landslide susceptibility in Ireland will be the compilation of a national database on previous landslide events. Climate change and the increase in the incidence of heavy rainfall are also believed to affect the stability of slopes.