It has been confirmed that a magnitude four earthquake struck off the west coast of the country this morning.
Hundreds of people across counties Mayo, Sligo and Galway experienced strong tremors in their homes and workplaces this morning, though there were no reports of injuries.
The earthquake struck 100 kilometres off the coast at Belmullet in Co Mayo just before 9am.
Although the earthquake's epicentre occurred at a depth of 60km, people along the west coast still reported feeling tremors.
Meanwhile at the National Data Centre for the Nuclear Test Ban Treaty in Dublin, new specialised equipment picked up the earthquake.
Using data from five stations monitoring seismic activity, the Irish National Seismic Network confirmed that this was the biggest earthquake every recorded off the west coast.
The National Seismic Network says that although some aftershocks are likely, they probably will not be strong enough to be felt on land.