Energy firm Cuadrilla has paused fracking in Lancashire again after more underground tremors were detected.
A series of “micro-seismic events” in Blackpool were recorded on the British Geological Survey website following hydraulic fracturing at the shale gas exploration site at Preston New Road, Cuadrilla said.
The biggest of the tremors, which was felt in Blackpool, was 1.5 local magnitude, and is the largest recorded since the controversial process began in Lancashire on October 15.
It occurred at about 11.20am, after fracking had finished for the day, the company said.
This is a red event under the traffic light system in place for monitoring seismic events during fracking, leading to a temporary halt to operations.
Recent research by the University of Liverpool suggests the impact of such a tremor would be like dropping a melon, Cuadrilla said.
A series of smaller events occurred earlier while fracking was taking place.
The company said in a statement: “Cuadrilla will pause and continue to monitor micro seismicity for at least the next 18 hours, in line with the traffic light system regulations.
“Well integrity has been checked and verified.”
A number of tremors have been detected at the Preston New Road site since fracking began on October 15, with work stopping whenever a quake of magnitude 0.5 or more is detected under the rules.
But according to the BGS, earthquakes with a magnitude of less than two are not usually felt and, if they are, it is only by people very close to the earthquake.
Tony Bosworth, Friends of the Earth campaigner, said: “Within a day of Cuadrilla re-starting fracking in Lancashire, there has already been another earthquake which means they’ve had to down tools.
“It appears that they cannot frack without triggering tremors. And instead of acknowledging that fracking needs to end, Cuadrilla are instead urging for regulations around earthquakes to be relaxed.
“We’ve always said that fracking poses risks for our climate and environment. After today’s quake, and with the effects of climate breakdown already happening around us, isn’t it time to put a stop to fracking once and for all?”