Question to the Department for Business, Energy and Industrial Strategy:

To ask the Secretary of State for Business, Energy and Industrial Strategy, what the evidential basis is for the decision to suspension hydraulic fracturing operations for 18 hours as a result of induced seismic activity of >0.5 magnitude.

Following minor seismic events at Preese Hall in 2011, an expert scientific review recommended that a traffic light system (TLS) be put in place, under which hydraulic fracturing operations should be paused if a seismic event was detected at or above a precautionary threshold of magnitude 0.5. The intention of the TLS was to minimise disturbance to local communities and to avoid harm to people or the environment. The TLS was developed in consultation with industry.

The Oil and Gas Authority monitors seismicity as part of their regulatory duties at shale gas sites and requires certain controls and requirements to be adhered to as set out in a Hydraulic Fracture Plan (HFP) which must be agreed between the operator and the regulators before operations can start. The TLS did not specify a pause period after a 0.5 magnitude event, however as a part of the HFP for their first well at Preston New Road, Cuadrilla proposed that they would pause for a minimum of 18 hours should a seismic event greater, or equal to, the 0.5 magnitude threshold be detected. The regulators considered that this was reasonable to allow them sufficient time to analyse seismic data and minimise the risk of trailing events.