5th March 2014
UK Shale conference report 4
Professor Peter Styles, one of the UK’s leading experts on seismicity, said the Blackpool earthquakes in 2011 might have been avoided if Cuadrilla had carried out 3d seismic surveys before it fracked.
The earthquakes, which had a magnitude of 1.5 ad 2.3, were caused by the injection of fluid into an area near a geological fault. The casing of the well at Cuadrilla’s Preese Hall site was deformed as a result. Following the earthquakes, the government imposed an 18-month moratorium on fracking in the UK.
Responding to a question at a London shale gas conference, Professor Styles, of Keele University, said 3d seismic survey data might have shown Cuadrilla how close the well was to the fault. He also said if the company had micro seismic monitoring data it would have seen a series of small seismic events which happened before the earthquakes. When pressed for an answer, he agreed that 3d surveying “would have reduced the risk” of the earthquakes.
He said some in the fracking industry complained that seismic surveying and monitoring was expensive. But it was not, he said, as expensive as waiting for the moratorium to be lifted. “I personally believe it [seismic data] is an essential part of the precursor [to fracturing]”.
Professor Styles said most of the earthquakes throughout the world that were associated with fracking were triggered: they would have happened at some point anyway. He warned the industry: “Do not inject large volumes of waste water over long period of times or you may trigger earthquakes.”
Professor Zoe Shipton, of Strathclyde University, said earthquakes sounded dramatic but she played down their importance. She said the magnitude of earthquakes triggered by fracking was unlikely to be more than t three. “We will never do any pile driving if we don’t want a magnitude of three. Plus we will probably have to ban some buses.” She said she was much more worried by spills of fracking fluids from a truck that hit a deer and overturned.
Since the earthquakes, Cuadrilla has carried out 3D seismic surveys in its licence area around Blackpool but it did not do any at Balcombe.