Scientists link two Irish Sea tremors to Ice Age - Belfast Telegraph

By Louise Hogan – 26 August 2013

The latest earthquakes recorded in the Irish Sea could have their origins in the last Ice Age.

Two sets of tremors recorded off the north-west coast of England were most likely due to 'glacial rebound' -- a process where the pressure built up by the weight of glaciers during the last glacial period thousands of years ago is slowly released.

Scientists recorded a 2.4 magnitude quake at 5.37am yesterday around 25km west of Fleetwood off the north-west coast of England -- and some 185km from Dublin.

The Irish National Seismic Network (INSN) reported a much stronger magnitude 3.2 quake in the same location, at a depth of 8km under the sea, less than five hours later.

The earthquake was felt throughout Fleetwood, Blackpool, Lancashire, and in Cumbria, with houses shaking but no major damage reported.

And the INSN's seismometers picked up the quake as far away as Donegal and Wexford.

Tom Blake, director of the INSN, said further tremors were possible in the coming days. Over the past six weeks smaller earthquakes have been recorded in the Irish Sea and along western parts of Britain.

"It is impossible to tell if stronger earthquakes will occur in the coming days and weeks, but aftershocks can be expected even if most if not all will be too weak to be felt," he said.

 Mr Blake, from the Dublin Institute for Advanced Studies (DIAS), which runs the INSN, said there had not been any "significant" seismic activity recorded in the spot where yesterday's earthquakes struck in the Irish Sea in recent years.

"The last earthquake recorded in this part of the Irish Sea occurred in 1843 and is estimated to have been a magnitude four quake," he said.

Yet, he stressed the cause was likely to be the same as other earthquakes felt around the UK and Ireland.

Mr Blake said both the UK and Ireland were far from any tectonic plate boundaries blamed for earthquake activity in other areas. "Much of the region is still experiencing quakes due to the removal of the weight of ice sheets," he said.

The scientist explained the movement of the land surface slowly returning to the pre-glacial shape results in earthquakes, particularly in the northern half of the islands.

The INSN recorded a 3.8 magnitude earthquake -- the largest ever recorded on mainland Britain -- in the Irish Sea, off the Welsh Coast, last May.

It was also felt in some parts of Dublin, Wicklow and Wexford. A month later another 2.8 magnitude earthquake was recorded in the same area.