An earthquake was recorded in County Wicklow on Sunday night, marking the first mainland seismic event in Ireland in nearly 18 months.

The British Geological Survey confirmed the tremor occurred at 11.30pm, a few kilometres south of Rathdrum at Avondale Wood, at a depth of 10 kilometres.

It is the first mainland earthquake since May 2024, when a magnitude 1.1 tremor struck near Ballybofey in County Donegal.

The Wicklow event follows two recent offshore quakes in the Irish Sea. On Thursday, a magnitude 1.3 earthquake was recorded off the coast of Southport, north of Liverpool. That came just a week after a magnitude 1.0 tremor was detected west of Dublin.

While Ireland is not known for frequent seismic activity, minor earthquakes do occur from time to time, with much of the activity concentrated in counties Wicklow and Donegal.

The small quakes are typically caused by natural adjustments in the Earth’s crust due to due to the removal of the weight of ice sheets. Most are imperceptible to the public, with only a few felt as faint shakes or rumbles.

Ireland’s most significant recent earthquake occurred in June 2012, when a magnitude 4.0 event off the west coast caused tremors felt across Mayo, Galway and Sligo. In 2019, Donegal experienced two earthquakes within three weeks. More recently, in May 2023, the Irish National Seismic Network confirmed a magnitude 2.5 earthquake near Glenveagh National Park at a depth of five kilometres.

The strongest recent earthquake in the Irish Sea was a magnitude 2.5 event on December 15, 2019. However, the most powerful quake ever recorded on mainland Britain occurred in July 1984, when a magnitude 5.4 earthquake struck the Llŷn Peninsula in North Wales. That event was felt across Ireland’s east coast, as well as in Wales and England.