A leading seismologist today confirmed earthquakes felt by Fylde coast residents were a “natural event” – and not part of any activity by gas firms in the area.
Shocked residents who felt two tremors yesterday morning had questioned whether they were connected to seismic testing currently being carried out by Halite Energy in Knott End or previous exploratory drilling work by shale gas firm Cuadrilla Resources Ltd.
Philip Mitchell, of Blackpool and Fylde Green Party, has called for a “proper investigation into what caused” the tremors.
But Glenn Ford, seismologist at the British Geological Survey, said: “These earthquakes appear to be no different from the few hundred or so natural events that are recorded by the BGS seismograph network every year and there is no reason to conclude they are cause of any fracking processes.
“An experienced analyst can usually distinguish between the seismic characteristics of man-made sources like explosions from natural events.
“The epicentres of these events are also many miles from Knott End.”
The first tremor hit the Irish Sea, 25km from Fleetwood, at 5.37am yesterday.
It measured 2.4 on the Richter scale and hit at a depth of 3km.
The second,in the same area, was recorded by BGS at 9.58am with a magnitude of 3.3 and at depth of 8km.
The tremors were felt in Fleetwood, Blackpool, Poulton, Thornton, Cleveleys, and as far away as Cumbria.
Derek Loynds, 77, of Norbreck Road, Norbreck, said: “I thought the chimney was coming off the roof.
“It worried me to death”
And Patricia Rogers, 56, of Green Drive, Cleveleys, said: “It made my bed and wardrobes shake. I thought the wardrobes were going to fall out.”
The Irish National Seismic Network (INSN) said the quakes were probably caused by stresses built up from the weight of glaciers covering land during the Ice Age.
INSN director Tom Blake said it was unusual that the earthquakes - measuring 2.4 and then a stronger 3.3 on the Richter scale - happened in the Irish Sea.
“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,” Mr Blake said.
Halite is due to finish its exploratory work, involving a series of controlled explosions to test the nature of the bed rock Over Wyre, this week.
Keith Budinger, chief executive of Halite Energy, said: “Our seismic survey work is only at a six metre maximum depth. The tremors were nothing to do with our work, it’s just too shallow.”
Cuadrilla Resources is the firm behind fracking – which is the process of injecting liquid into the ground at high pressure to release gas from shale rock –on the Fylde coast.
It has sites in Weeton, Westby and Singleton.
In 2011, a tremor of magnitude 2.3 hit the Fylde coast on April 1, followed by a second of magnitude 1.4 on May 27. They were later linked to Cuadrilla’s drilling at Preese Hall, Lancashire, by the BGS.
BGS is now encouraging people to complete an online macro-seismic survey so it can calculate how far away the tremors were felt.
Visit www.earthquakes.bgs.ac.uk/earthquakes/ recent_events