Cuadrilla has confirmed it will continue fracking at its site in Lancashire despite a further tremor being detected underground.
The company called a temporary halt to the work after a “tiny” tremor was detected on Tuesday afternoon at the shale exploration site at Preston New Road while fracking operations were taking place.
Following more work on Wednesday morning, Cuadrilla confirmed a second tremor of 0.48 local magnitude had been detected, but stressed the two “tiny seismic events” were within operating expectations.
It confirmed hydraulic fracturing operations will begin again on Thursday morning and said both tremors were well below the magnitude capable of being felt on the surface.
It added: “Following on from hydraulic fracturing operations today Cuadrilla has detected micro seismic activity of 0.48ML.
“This is within operating expectations and the sophisticated system of monitoring in place is working as it should.
“These are tiny seismic events that are being detected by our monitors as we fracture the shale rock 2km underground and are many hundreds of orders of magnitude below what is capable of being felt much less cause damage or harm at surface.”
The 0.4ML tremor on Tuesday was classed as an amber event as part of the traffic light system in place for monitoring seismic events during operations
Cuadrilla said it was required to reduce the rate at which it was pumping fracturing fluid once the seismic event had been detected, but it had “adopted extra caution” and had stopped pumping for the day in response.
Work got under way again on Wednesday morning, however fracking had stopped before the second tremor was detected.
The controversial fracking process began earlier this month after an environmental campaigner failed in a High Court bid to block operations.
The exploration taking place at Preston New Road is the first fracking in the UK for seven years, after work by Cuadrilla was halted in 2011 following two tremors near Blackpool.