CITIZEN POWER ALLIANCE

The only company in Britain using hydraulic fracturing to release natural gas from shale rock said Wednesday that the controversial technique probably did trigger earth tremors in April and May.

But a report commissioned by Cuadrilla Resources, which is drilling for gas in the area outside the northwestern English coastal resort town of Blackpool, cautioned that the tremors, measuring 1.9 and 2.8 on the Richter scale - were due to an unusual combination of geology and operations and were unlikely to happen again.

Cuadrilla is the only company currently extracting shale gas using hydraulic fracturing - a controversial technique by which a mix of water, sand and chemicals are pumped deep inside underground rock formations to free the gas.

Fracturing operations were suspended on May 27 following the detection of a tremor centered just outside Blackpool.

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