The increasingly large seismic events at Cuadrilla Resources’ site in Northern England have revived UK public concern about fracking that led to a lengthy suspension of operations seven years ago, writes Anamaria Deduleasa.

Since Cuadrilla resumed operations last week at Preston New Road, there have been seven tremors greater than 0.5 magnitude, the threshold above which operations must be paused for 18 hours. The largest of the tremors was 2.9.

In 2011, Cuadrilla’s operations triggered a 2.3 seismic event that was followed by fracking being suspended for years and led to the current system of tight regulatory thresholds. Current operations have been suspended while the Oil & Gas Authority investigates.

The British Geological Survey expects several hundred natural seismic events with a magnitude of 1 or above each year, regardless of fracking, noting that anything below a 2 magnitude is “unlikely to be felt at the surface”.

Nevertheless, reports from locals claimed the largest of the events was indeed felt.

Either way, political tremors followed. Politicians in the Labour Party have already jumped on the 'ban fracking' bus, a week after the Conservative Party came out in support of shale gas.

Cuadrilla has tried to reassure locals, but its strategy to underline how minor the tremors feel by comparing these to ‘a toddler playing on a wooden floor’ (2.1), ‘a shopping bag falling on the floor’ (1.6), ‘bouncing a tennis ball’ (1.2), has done little to persuade the sceptics.

With the company itself publicly questioning whether fracking is viable under current regulations, its opponents could now claim it is not, regardless of thresholds.