The Irish Sea has experienced its second seismic event in just seven days, with a magnitude 1.3 earthquake recorded on Thursday morning, according to the British Geological Survey (BGS).

The tremor struck at 10:18am a few kilometres off the coast of Southport, a seaside town located just north of Liverpool.

It occurred at a relatively shallow depth of 3 kilometres and was detected by local seismograms. It is unlikely that the quake would have been felt on the mainland.

This latest quake follows a magnitude 1.0 event in the same region last Thursday.

While earthquakes in Britain and Ireland often come as a surprise, minor tremors are not unusual. These 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.

The Irish Sea has seen occasional seismic activity, particularly offshore near Wexford and Skerries in Dublin. The most recent Irish Sea quake prior to this week occurred on May 22 and registered a magnitude of 1.5. In March, a 1.4 magnitude tremor was recorded in the Celtic Sea, about 95 kilometres southeast of Rosslare, County Wexford.

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.