‘Baseline’ set in study for quake 
fear in fracking

The findings come from an analysis of 1,769 seismic events between 1970 and 2012 of 1.5 magnitude and above, the minimum detectable threshold.

It reveals there has been a sharp drop in the number of earthquakes since the 1980s, when the coal industry declined.

Since 1999, human activities have resulted in on average at least three onshore earthquakes each year of magnitude 1.5 or above, which can often be felt, the study published in the journal Marine and Petroleum Geology found.

These include two tremors caused by fracking in Lancashire in 2011 before a temporary ban was imposed on the practice.

Professor Richard Davies, who led the research, said it provided the world’s first baseline for the impacts of fracking, or hydraulic fracturing, in the UK before exploitation of shale gas through the process is ramped up.

Coal mining has declined across the country and the closure of Hatfield Colliery, in Doncaster, this year marked the end of mining in South Yorkshire.

The Government has said it is going “all out for shale” to boost energy security and the economy but opponents fear fracking – in which liquid is pumped deep underground at high pressure to fracture rock and release gas – could cause earthquakes.

Prof Davies, of Newcastle University, said: “Earthquakes triggered or induced by humans are not a new concept for us here in the UK, but earthquakes related to fracking are. Understanding what the current situation is and setting a national baseline is imperative, otherwise how can we say what the impact of fracking has been nationwide?”

He said the national baseline, along with seismic monitoring at fracking sites, could show the impact of shale gas exploration on numbers of earthquakes.

He added: “Historically, fracking-related earthquakes have been small, but the UK is criss-crossed with faults – some of which may be critically stressed – and if triggered these could result in earthquakes that people can feel.”

The research looked at around 8,000 onshore seismic events recorded by the British Geological Survey between 1970 and 2012, with a range of origins including mining, industrial explosions, natural causes and lightning strikes.

Of the 1,769 events that were 1.5 magnitude or above, at least 21 per cent were related to human activity, at least 40 per cent were naturally occurrences and 39 per cent “undefined”.

Since 1999, there were between zero and eight quakes a year with an average of three.

A spokesman for the Department of Energy and Climate Change said: “As recognised by this research, there are no documented cases of shale gas operations causing subsidence or earthquakes which have caused damage at the surface.

“We have extremely robust controls in place to mitigate seismic risks and in the unlikely event that any operations were to pose a risk, we have the powers required to close them down.”

North Yorkshire County Council is considering an application from Third Energy to carry out test-fracking at a site in Kirby Misperton in Ryedale.