The third and what is believed to be the largest tremor yet has been recorded at Cuadrilla’s fracking site in Lancashire.
Operations have been suspended at the Preston New Road site near Blackpool following the 2.9 magnitude tremor at 8.30am on Monday.
It comes after two other tremors were previously recorded as the largest at the time.
Any tremor that measures 0.5 or above means fracking must be stopped temporarily while tests are carried out.
Cuadrilla said no hydraulic fracturing has been carried out over the weekend and that fracking has been suspended.
The company added: “We appreciate 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.”
The Oil Gas Authority confirmed the seismic event, “which was felt by people in the area”.
Another micro seismic event was also detected at the shale gas exploration site just before 10.20pm on Monday.
A Cuadrilla spokesperson said: “Cuadrilla was not hydraulically fracturing at the time and hydraulic fracturing has not been carried out over the weekend. This event lasted for a couple of seconds and the average ground motion was 0.1mm per second.
“Being of a low magnitude and with very low ground motion, it is unlikely to have been widely felt. Operations at Preston New Road remain suspended. The well integrity has been verified and remains unaffected.”
A new report suggests the capacity of shale gas reserves in the UK could be “significantly lower” than estimates previously set out.