LONDON, April 17 (UPI) -- Fracking, the controversial gas extraction method that triggered earth tremors in Britain last year, should continue but under strict conditions, a panel said.
Near Blackpool, test fracking or "fracturing," involving pumping water and chemicals into shale rock at high pressure to extract gas, was halted in 2011 when two earthquakes were felt at the surface.
A government-appointed panel of experts said it believes there likely will be more quakes but they would be too small to do structural damage above ground, so fracking could resume but only with more monitoring, the BBC reported Tuesday.
The panel agreed with a report from Caudrilla, the company conducting the Blackpool tests, that fracturing at the site did cause two earthquakes of 2.3 and 1.5 magnitudes in April and May.
"[Cuadrilla's experts] said there was a very low probability of other earthquakes during future treatments of other wells," one of the report's authors, Peter Styles of Keele University, said.
"We agree that [last year's] events are attributable to the existence of an adjacent geological fault that had not been identified."
However, fracking is unlikely to produce any temblors larger than a magnitude-3, the panel said.
"There's no record of a quake at this size doing any structural damage," Styles said. "But they would be strongly felt, and there is a possibility of superficial damage."