LONDON (Reuters) - Shale gas exploration triggered small earthquakes near Blackpool in northwest England earlier this year, UK firm Cuadrilla Resources said, adding to concerns about the safety of a technology that is transforming U.S. energy markets.
A spokesman said on Wednesday tremors were triggered by pumping vast quantities of water at high pressure 3 kilometres underground through drill holes in a process known as hydraulic fracturing, or fracking, which is designed to prop open shale rocks and release trapped gas.
"It is highly probable that the hydraulic fracturing of Cuadrilla's Preese Hall-1 well did trigger a number of minor seismic events," a report commissioned by the company said.
Environmentalists on both sides of the Atlantic have lobbied politicians to ban fracking on concerns it leads to pollution of ground water and leakage of gas into the atmosphere.
Britain suspended fracking following the May tremor and commissioned a report into the process, but Cuadrilla has since said there was little risk that the tremors in April and May of 2.3 and 1.5 on the Richter scale, respectively, would be repeated.
