Almost 50 geoscientists have urged the government to commission an urgent review of the fracking earthquake limit, which they suggest should be raised to allow the industry to expand.
They say that the scientific rationale of the 0.5 magnitude limit before fracking must cease is debatable. They call for a “realistic regulatory framework”.
The letter to the Times, signed by 49 scientists, will increase pressure on the government to accede to the fracking industry’s demand for a review of the limit. The business department repeated this week that it had no plans to review the limit despite Cuadrilla and Ineos both saying that fracking would not be viable unless it was raised.
Cuadrilla resumed fracking in October after a seven-year hiatus and was forced to stop six times over the next two months after breaching the limit at a site in Lancashire. The interruptions meant that it was unable to pump enough sand down the well to hold open tiny fractures in the rock through which gas flows.
The letter says the limit is “very far below the levels set in other countries, or for other comparable industries in the UK (such as quarrying, mining and deep geothermal energy). It is widely believed by industry, and among informed academics, to be so low that it threatens the potential development of a shale gas industry in the UK.”
In the US the limit is 2.7 to 4.5 depending on the state, although fracking often takes place in less populated areas. The Richter scale is logarithmic, meaning a magnitude 4 tremor is 3,162 times higher than magnitude 0.5. The strongest of the earthquakes caused by Cuadrilla was 1.5.
Under the government’s “traffic-light system” for fracking, pumping has to proceed at a reduced rate after a tremor below 0.5 and stop for 18 hours after one of 0.5 or above.
The letter, co-ordinated by Professor Quentin Fisher of Leeds University and Professor Ernest Rutter of the University of Manchester, concludes: “We urge the government to instruct the Oil and Gas Authority to commission an expert review of the present traffic-light system threshold levels without delay.”
The scientists note that when the limit was set in 2012 the government said that it would be subject to review as experience of fracking developed.
Professor Rutter said: “When the traffic-light system was first developed, there was limited UK data available upon which to base it. That has now changed, and there is a wealth of new data available specific to our geology.”