A Cuadrilla report into the Lancashire earthquakes of summer 2011 show fracking fluid disrupted a previously unknown fault. This fault then caused the earthquakes. A similar inability to find faults under Balcombe would lead to a pollution of Sussex’s groundwater.
The report summarises that the cause of the earthquakes was frack fluid injection into this unidentified fault plane: “it can be concluded that direct injection into the fault induced the seismicity”. (p50).
An objective of the report was “Evaluation of potential for upward fluid migration” (p52). Here the report concludes “in the worst case, the fluid could migrate upwards along a potential fault plane by 2,000 ft”.
In its own report, therefore, the company admits both that it is unable to identify fault planes, and that these faults may extend 2000 ft upwards.
In terms of Balcombe, Cuadrilla’s estimates that the water table sit at a max depth of 1000 ft (see 6.3.11 of the company’s submission to parliament). The company intends to frack at 2667 ft. An upward migration of 2000 ft, therefore, runs through the aquifer and within 667 feet of the surface.
A similarly unidentified fault in Balcombe, therefore, would clearly pollute Balcombe’s water supply.
The company rightly claims that the geology is different in Sussex. The point remains, however, that the earthquake-causing fault was unidentified. As Tony Ingraffea (Professor of Rock Fracture Mechanics at Cornell University) notes, ‘Fracking has always been unpredicatable, always will be’.