15 November 2011 – From The New York Times: A British seismologist has claimed that two minor earthquakes in north western England “appeared to correlate closely” with the use of hydraulic fracturing – a method of extracting natural gas from wells that has raised concerns about environmental and seismological risks in the United States.
During fracking, sand, water, and chemicals are injected at high pressure into shale rock in order to split it and release trapped gas.
Brian Baptie, seismic team leader with the British Geological Survey, said in an article in The New York Times, that two quakes near Blackpool, England appear to have been caused by nearby fracking operations being conducted at a well by Caudrilla Resources.
Mr Baptie said that the high-pressure injection of water could have reduced stresses on a fault close by, causing it to slip.
While the quakes registered only magnitude 2.3 on April 1, and 1.5 on May 27, Caudilla postponed all fracking operations at the end of May, “while it interprets seismic information received from monitoring information located around the site,” according to a company statement.
The three wells drilled by the company are the only shale-gas wells so far in Britain. In May, the World Wildlife Federation in Scotland, called for a ban on fracking in that country. The practice has already been banned in France.
Fracking is now widespread in the US and has been blamed by some landowners, environmentalists and public officials for contaminating waterways and drinking water supplies. Some critics have also said that the technology could cause significant earthquakes.
But Stephen Horton, a seismologist at the University of Memphis, said, “Generally speaking, fracking doesn’t create earthquakes that are large enough to be felt.” Even so, Mr. Horton said that after looking at the British Geological Survey’s analysis of the Blackpool earthquakes, “the conclusions are reasonable.”