The controversial operation began 11 days ago after an environmental campaigner failed in a High Court bid to block it. Fracking restarted on Saturday morning before a second tremor was detected. They are tiny movements that occur below ground. The company only has permission to frack until that time on Saturdays.
The natural disaster is the 14th recorded by the British Geological Survey and the joint biggest since fracking began last Monday.
A spokesman for the the Oil and Gas Authority said: "While the operations at the Preston New Road site have been created to minimise any disturbance, minor events like these were expected".
Fracking has been paused at British shale gas company Cuadrilla's Lancashire site after a fourth "micro seismic" event in four days.
Hydraulic fracturing, or fracking, involves pumping water and chemicals at high pressure to fracture shale rock and release gas.
Friends of the Earth has helped to organise a petition, signed by some 300,000 people, to stop the fracking through the planning system.
A study found it was "highly probable" the test drilling for shale gas caused the tremors.
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The tremor was classed as a "red event" as part of the traffic light system regulated by the Oil and Gas Authority.
A spokesperson said: "Work will now pause for at least 18 hours and is expected to recommence in the morning".
The UK's Energy Minister Claire Perry had a private meeting with oil and gas firms in May, months before fracking resumed in the UK earlier this month for the first time in seven years, but she failed to record that meeting in a transparency register, The Guardian reported on Friday.
Three protesters jailed for blocking access to the site walked free after the court of appeal quashed their sentences as last week, calling them "manifestly excessive".
The government subsequently denied it has any plans to relax the rules.
A government-appointed panel recommended greater monitoring and said operators should observe a "traffic light" regime, with tremors of 0.5 or above triggering a "red light" and an immediate halt.