Fracking at the UK’s only active site has been halted after the largest tremor yet recorded.
Seismic activity with a magnitude of 1.55 was detected at the Preston New Road site near Blackpool on Wednesday night, Cuadrilla said.
Previously, the largest tremor recorded at Little Plumpton was 1.5.
Cuadrilla said the latest would not have been felt by most locals and likened it to “a large bag of shopping dropping to the floor”.
The British Geological Survey measured the tremor as 1.6.
Any tremor measuring 0.5 or above means fracking must be temporarily stopped while tests are carried out.
Cuadrilla said it had suspended activity for 18 hours after the “small” tremor, and was monitoring the site.
It said the shale gas well was intact.
Drilling at the site started on 15 October 2018 after campaigners tried to stop the process with an injunction but failed.
It had previously been stopped in 2011 over earth tremor fears.
The process of fracturing rocks with a high pressure mixture of water and chemicals to extract shale gas has long been seen by the UK government as an important potential energy source.
However, the process of extracting unconventional gas in the UK has brought a flurry of protests and legal challenges.
Cuadrilla said “minor movements of this level” were to be expected and could not “cause harm or damage to anyone of their property”.
Anti-fracking campaigners argue the process poses risks to the environment.