Last year, two earth tremors were detected following Cuadrilla’s hydraulic fracturing operations at Preese Hall. The first took place on 1st April 2011 and measured 2.3 on the Richter Scale. To determine whether this was due to hydraulic fracturing, Cuadrilla worked with Keele University and the British Geological Survey (BGS) to set optimally placed seismometers to monitor ground movements around the active well sites as well as the surrounding area.
It was during the fourth fracture treatment at Preese Hall when a second tremor measuring 1.5 was recorded on 27th May 2011. Following this and after discussions with the Department of Energy and Climate Change, we voluntarily paused hydraulic fracturing operations while a report was commissioned to discover if there was a link between seismicity and fracturing.
Shortly after the report into these tremors was released, Prof. Mike Stephenson, Head of Energy at the British Geological Survey (BGS), told the Shale Gas Environmental Summit:
“The tremors were way too small to cause any damage”
Professor Mike Stephenson, BGS, November 2011
The main findings of the independent Geomechanical Study of Bowland Shale Seismicity report were: