Fracking has resumed again in Lancashire after a minor earthquake on Tuesday led to an 18 hour suspension.
Energy firm Cuadrilla halted the work at the Preston New Road site in line with regulations. But they say the micro-seismic event measuring 1.1 magnitude was below anything that would cause damage or harm.
Two smaller tremors affected the site last week.
Anti-fracking campaigners argue the process, to extract shale gas, poses risks to the environment.
According to the BGS, earthquakes with magnitude of less than two are not usually felt and, if they are, it is only by people very close to the earthquake.