A mining company has halted drilling for shale gas in England after scientists said two small earthquakes might be linked to the controversial process of fracking.

The British Geological Survey recorded a 1.5-magnitude quake Friday near Blackpool in northwest England, within two kilometres of the gas exploration site. A 2.3-magnitude quake was recorded last month.

The geological survey's head of seismology, Brian Baptie, said Tuesday the two quakes appeared to have "a similar location and mechanism."

U.K.-based Cuadrilla Resources says it has stopped hydraulic fracturing, or fracking — the process of extracting gas by pummeling rocks deep underground with high-pressure water, sand and chemicals — while it studies data from the quakes and consulted with experts.

"We expect that this analysis and subsequent consultation will take a number of weeks to conclude and we will decide on appropriate actions after that," said chief executive Mark Miller.

Shale gas extraction, pioneered by the U.S. and Canada, is forecast to boost global recoverable natural gas resources by 40 per cent. But ecologists are alarmed by its environmental impact.

The biggest worry is that cancer-causing compounds used in the process could pollute water supplies. High levels of methane gas also have been found in tap water near some U.S. drilling sites, with YouTube videos showing people apparently setting fire to tap water. (read more)