Operations at the Preston New Road site are continuing following a series of minor seismic events, (the most recent on 14 December) which have exceeded our magnitude 0.5 limit for caution. This threshold is set at a level well below what could be felt at the surface.
Following any event that exceeds the threshold, the operator is required to immediately pause, reduce pressure and monitor for any further events.
During these pauses, the OGA compares the location, magnitude and ground motion of these minor seismic events to the operator’s approved Hydraulic Fracture Plan (HFP).
To date the OGA has been satisfied that these events have been in line with the geological understanding set out in the HFP and that the risk of induced seismicity is being appropriately managed.
OGA Director of Regulation, Tom Wheeler, said: “We are continuing to take a cautious approach and have strict controls in place so that any event over the threshold results in a pause in operations to allow us to review the event and check that the operator’s approved plan is still valid. This pause can be extended if required.”
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