A 2.1-magnitude tremor has been reported at the UK’s only active fracking site – days after a 1.55-magnitude movement.
Saturday night’s “micro seismic event” at Cuadrilla’s site near Blackpool is believed to be the biggest-ever fracking-related tremor in the UK.
The company said the tremor, detected at 11.01pm, lasted for about one second and occurred when no fracking was taking place.
A spokeswoman for the company said: “Minor ground movements of this level are to be expected.
“While this event has been felt by people on our site and some local households, it is well below anything that can cause harm or damage to anyone or their property.”
Under UK rules, work must be suspended for 18 hours if seismic activity with a magnitude exceeding 0.5 is detected.
Cuadrilla has previously described this limit as “exceedingly low” and wants a review of the rules, which are much tougher than in the US.
According to the British Geological Survey, the tremor was 1.2 miles deep and was felt by residents in areas including Great Plumpton, Blackpool and Lytham St Annes.
Cuadrilla claims Wednesday’s tremor would have felt similar to someone dropping a large bag of shopping on the floor.
Fracking, or hydraulic fracturing, involves injecting water and chemicals at high pressure to break up rock and extract gas.
However, it can cause tremors and is opposed by environmentalists who say it contaminates drinking water, pollutes the air and water and contributes to climate change.
There have been regular protests at the Lancashire site.
Cuadrilla says fracking work will be completed by the end of November, followed by flow testing of the well, with results expected early in 2020.
It hopes exploratory tests will show the potential of shale gas for the UK and estimates around 1,300 trillion cubic feet of gas is contained in the area.
The government says shale gas could be an important new domestic energy source reducing dependency on imports as well as delivering economic benefits.