A magnitude 4.0 earthquake has been recorded off the coast of Co Mayo this morning, close to the Corrib gas field.
A spokesman for the British Geological Survey, which monitors seismic activity in the UK and Ireland, said the quake happened just before 9am, 60km west of Aughleam near Belmullet. It was at a relatively shallow depth of 3km.
Tremors were felt in counties Mayo, Sligo and Galway with some local radio stations receiving calls from listeners who described houses shaking.
Tom Blake, director of the Irish National Seismic Network, said the region had never experienced an earthquake of this size before.
The largest earthquake recorded in Ireland occurred in 1984 when a magnitude 5.4 quake struck off the coast of Wales causing tremors and structural damage along the east coast of Ireland. Micro tremors were felt in parts of north Co Donegal in January and March near Buncrana.
Minister for Energy and Natural Resouces Pat Rabbitte said all evidence so far pointed to this being a “naturally occurring earthquake”. The epicentre was on a known fault line west of the Irish shelf, and was slightly larger than usual, he said.
Mr Rabbitte said there was “no link” to the Corrib gas field in Co Mayo, which was not in production.
British Geological Survey seismologist David Galloway said the quake would have been felt in many areas of Connacht.
"We have been getting reports of the windows rattling, that the shaking felt like a lorry or some vehicle smashing into the back of the house, which is typical of the felt reports of earthquakes," he said. "One report described it as like a steamroller going down the road."
Mr Galloway said he had not heard of any damage to property and was not expecting any. "It is quite a small earthquake, it is only significant for the fact that the UK or Ireland does not get the big earthquakes of Italy or Turkey," he added.
The area where it happened today is in the middle of a plate which is moving further from America, far from a faultline and hence the force was not on the scale of areas where they collide, like California or Japan.
There would not have been enough dislocation of the sea floor to create any big waves and there is no chance of a tsunami, that is not going to happen," he added. "It is not a warning of anything bigger to come, we do not usually get the big earthquakes."
Additional reporting: PA