The epicentre of an earthquake which struck Chester in 1750 is close to two potential ‘fracking’ sites.
Data analyst John Murray made the discovery after using open data from the British Geological Survey and Ordnance Survey to map the possible sites at Bridge Trafford and Barrow.
His information reveals nearby geological fault lines and the epicentre of the earthquake which had a magnitude of four, one of the largest recorded in UK history.
Fracking – or hydraulic fracturing – was temporarily suspended in the UK in 2011 following earth tremors in Blackpool.
Mr Murray, a professional data analyst, is not involved in the anti-fracking campaign and stresses he is not a geologist but says the data does ‘raise questions’ about whether fracking can be carried out safely given the sites are only about a mile from the epicentre and even closer to the fault lines.
He commented: “Do I think fracking is safe? I think there is insufficient data to say yes or no. The data from the US and the British Geological Survey suggests it probably isn’t. I think further study is needed.”
Star Energy Ltd, owned by IGas, last year bought a field at Bridge Trafford for £141,000 with campaigners now talking about the possibility of setting up a protest camp on the land, not far from The Chester Fields pub and restaurant. And the company also bought an option on a nearby field to the south of Warrington Road in Barrow, owned by David William Pym.
The energy firm says any decision over gas exploration – and whether that would be for coal bed methane or shale gas – will come down to the results of seismic testing.
Shale gas is extracted through a process called hydraulic fracturing or ‘fracking’ which involves injecting large volumes of water, sand and chemicals into the rock formation which causes it to break apart and release natural gas.
The US Geological Survey has just released first-ever maps showing potential ground-shaking hazards from both human-induced as well as natural earthquakes, with 7m Americans said to be at risk from man-made earthquakes.
Anti-fracking campaigner Ben Dean is worried about the proximity of the latest IGas sites to the geological faults saying the large amounts of water pumped underground have the effect of ‘lubricating’ the tectonic plates.
But he is even more concerned the activity could damage the aquifers from which drinking water is extracted and said there was no facility for cleaning up any contaminated water returned to the surface.
IGas spokesman Gordon Grant is confident people would be reassured by the process employed to determine which sites to pursue, which took into account the 'very best' geological picture available.
He said decisions were based on the science and data gathered through 3D seismic testing plus other information from the British Geological Survey and historic coal boreholes.
A contemporary account of the 1750 Chester earthquake was provided by Robert Paul who wrote: “I can’t help informing you (as it is a matter of concern to everyone) that on Monday night late, about 10 o’clock, we felt in this city a shock of an earthquake.
“It was sensibly felt by all or most of the inhabitants. A few bricks were shook off a chimney in Forest Street; several house-bells were rung; the sentry at the castle was shook off his seat in the sentry box; the houses all over town were shaken and the people terribly frightened and alarmed.”
On February 27, 2008, people in Cheshire and across England felt an earth tremor after a quake measuring 5.2 on the Richter scale with its epicentre near Market Rasen, Lincolnshire. Buildings shook shortly before 1am with some people reporting the tremors were strong enough to wake them.