Shale gas fracking 'probable' cause of Lancashire quakes
Controversial 'fracking' technique to extract gas from the ground was the 'highly probable' cause of earth tremors, report finds.
Two earthquake tremors in north-west England earlier this year were probably caused by controversial operations to extract gas nearby, a report by the company responsible has concluded.
The two tremors, which were felt by people just outside Blackpool, but did not cause any known damage, were reported in April and May, measuring 2.3 and 1.5 on the Richter scale. Since the second event, Cuadrilla Resources has stopped "fracking" operations — where water is injected into rocks at high pressure to extract gas from the cracks.
The report, by a team of European seismic experts not usually employed by the company, concluded it was 'highly probable' that the two main tremors and a series of aftershocks were caused by Cuadrilla's operations at the Preese Hall-1 Well in Lancashire.
It said, however, that the cause was an 'extremely rare' combination of factors including a pre-existing fault in the rocks, and that it was 'unlikely' to occur at other sites in the Bowland Basin, where Cuadrilla is hoping to exploit an estimated 200 trillion cubic feet of shale gas.
'If these factors were to combine again in the future, local geology limits seismic events to around magnitude three on the Richter scale as a "worst-case" scenario,' added a company statement.
Photo credit: Cuadrilla
Article continues: The Ecologist