Cuadrilla was forced to halt fracking at its shale gas site near Blackpool in Lancashire on Wednesday night after triggering the largest tremor recorded at the location.
The tremor closed down operations at the Preston New Road site shortly after it was detected at 8.46pm.
The shutdown comes less than a week after Cuadrilla started fracking its second well on the site after abandoning the first well following multiple shutdowns because of tremors.
Fracking, or hydraulic fracturing, is a way of extracting natural gas from shale rock formations that are often deep underground. It involves pumping water, chemicals and usually sand underground at high pressure to fracture shale – hence the name – and release the gas trapped within to be collected back at the surface.
The technology has transformed the US energy landscape in the last decade, owing to the combination of high-volume fracking – 1.5m gallons of water per well, on average – and the relatively modern ability to drill horizontally into shale after a vertical well has been drilled.
In England, the government placed a moratorium on fracking in November 2019 after protests, legal challenges and planning rejections. A year earlier, the energy company Cuadrilla was forced to stop work at its Preston New Road site in Lancashire twice in four days due to minor earthquakes occurring while it was fracking. The tremors breached a seismic threshold imposed after fracking caused minor earthquakes at a nearby Cuadrilla site in 2011. In March 2019 the high court ruled that the government's fracking guidelines were unlawful because they had failed to sufficiently consider scientific evidence against fracking.
The fracking firm said the “microseismic event” measured 1.55ML on the Richter scale, which it likened to “a large bag of shopping dropping to the floor”.
The tremor is higher than the previous record quake, which measured 1.5ML at Little Plumpton in December 2018, and easily breaches the government’s 0.5ML limit on seismic activity.
A company spokesman said: “Most local people will not have felt it due to its small size.”
Jamie Peters, a campaigner at Friends of the Earth, said even small vibrations at ground level can be a sign of far more damaging impacts deep underground.
“It’s obvious that fracking can’t be done without triggering earthquakes. This latest quake is a sign that Cuadrilla just can’t stick within the regulations they agreed,” he said.
Lee Rowley, a Conservative MP for North East Derbyshire, said: “The industry signed up to the seismic regulations years ago and told us they could operate within the limits. This just proves again that fracking isn’t going to work in the UK and the companies should give up flogging a dead horse.”
Cuadrilla has blamed the earthquake rules for stifling the UK’s nascent shale industry. It has called for a government review of the rules, and extra time to drill after its current fracking licence expires in November.
“Minor movements of this level are to be expected and are way below anything that can cause harm or damage to anyone or their property,” the spokesman said.
Ministers hinted last week that they are considering a review of the system after lending support to Cuadrilla’s campaign.
A government spokesman said: “Shale gas could be an important new domestic energy source, reducing the level of gas imports while delivering broad economic benefits, including through the creation of well-paid, quality jobs.”
Doubts have been cast about the claims because of recent research from the University of Nottingham, which found that the UK’s shale gas reserves may deliver only a fraction of the gas promised by fracking firms and government ministers.
The government responded to the study by saying that exploration is necessary to understand whether shale is safe and economic.
“The government is supportive of shale gas exploration in order to understand the size of the opportunity here in the UK,” a spokesman said.
