How fracking caused earthquakes in the UK - environment - 02 November 2011 - New Scientist - 2 views
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April and May this year, two small earthquakes struck the UK near the town of Blackpool.
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hydraulic fracturing, known as fracking
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controversial process to extract natural gas by fracturing the surrounding rock.
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fracking caused the earthquakes.
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magnitude-2.3 earthquake occurred on 1 April, followed by a magnitude-1.5 quake on 27 May.
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Preese Hall drilling site
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Cuadrilla Resources was using fracking to extract gas from a shale bed.
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(BGS) suggested that the quakes were linked to Cuadrilla's fracking activities.
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link with fracking has now been confirmed by an independent report commissioned by Cuadrilla, Geomechanical Study of Bowland Shale Seismicity
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induced by direct injection of fluid into the fault zone."
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two geologists
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fracking could – and most likely did – provoke the quakes.
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injecting huge volumes of water into the rocks surrounding a natural gas deposit
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water fractures the rocks, creating dozens of cracks through which the gas can escape to the surface.
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UK quakes were not caused by the violent rupturing of the rocks
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water
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lubricates the rocks and pushes them apart, allowing them to slip past each other
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oiling the fault," says Brian Baptie of the BGS.
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Fracking has been going on in the US for decades
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become much more common in recent years
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evidence
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causes earthquakes
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"This is one of the first times felt earthquakes have been associated with fracking," Baptie says.
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Cuadrilla report says the earthquakes occurred because of a rare combination of circumstances
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fault was already under stress
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brittle enough to fracture and had space for large amounts of water that could lubricate it.
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unlikely to happen again
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small faults are probably common in deep rocks
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given the same injection scheme in the same well, that there could be further earthquakes," he says.
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If earthquakes begin to occur, it could reduce the flow of water into the well, or even pump it back out, preventing the bigger quakes.
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damage
