The UK’s only active fracking site has been hit by a series of tremors within the past week, including one believed to be the country’s largest from the gas extraction practice.
A quake measuring 2.9 on the Richter scale was recorded in the area of Cuadrilla’s operation near Blackpool, Lancashire, at 8.30am on Monday.
This followed a “micro seismic” event with a magnitude of 2.1 on Saturday and another measuring 1.55 on Wednesday, which forced the gas exploration site to pause activities.
Cuadrilla said that no hydraulic fracturing was taking place at the time of Monday’s tremor and that none was carried out over the weekend.
“We appreciate that this has caused concern for local people and, by way of reassurance, it is worth noting that this event lasted for around a second and the average ground motion recorded was 5mm per second. This is about a third of that permitted for construction projects,” it added.
The quick succession of quakes is likely to reopen the debate around hydraulic fracturing, or fracking, a technique that involves pumping water and chemicals into shale rock to release hydrocarbons.
Stephen Hicks, a seismologist at Imperial College London, tweeted that the latest induced earthquake was located within a few hundred metres of the Preston New Road site.
“With its shallow depth, it will have likely been felt quite strongly by people living close to the epicentre,” he wrote.
Cuadrilla said the integrity of the well was unaffected and that it was working with a team of regulators that monitors its activities to investigate the incident. Fracking would remain suspended during this time.
The latest tremor was bigger than a magnitude 2.3 event in 2011 at another site, also near Blackpool and no longer in operation, which led to a seven-year moratorium on fracking in the UK.
Jamie Peters, a campaigner with Friends of the Earth, said: “This issue of earthquakes in connection to unwanted fracking has always been serious but now it is getting out of hand.
“It’s clearly not under control and at this point there is only one thing that can fix this situation: a ban, right now.”
Cuadrilla has said that the Preston New Road exploration site is the most regulated and monitored site in Europe and the systems in place are working as they should.
The private equity-backed company started fracking there last year, but its work has been interrupted on a number of occasions.
The disruptions last year meant it was only able to partially frack one well. This month it started work on a second as it tries to gather more data to persuade policymakers and regulators that the rules governing seismic events should be loosened.