LONDON (Reuters) - Britain could safely raise the limit for tremors at gas fracking sites, two seismologists said on Tuesday.
Fracking at Cuadrilla’s Preston New Road site in Lancashire, northwest England was halted several times last year after seismic activity exceeded limits put in place under Britain's traffic light regulation system.
Under the system work at fracking sites must be halted for 18 hours if seismic activity of magnitude 0.5 or above is detected.
Cuadrilla, the only company to have fracked for gas so far in Britain, has said the current seismic regulations are too stringent and could thwart the industry.
"Existing regulations are quite conservative and are set at a level that is unlikely to be felt," Brian Baptie, head of Seismology at the British Geological Survey, said at a briefing with journalists.
He said the limit could safely be raised to magnitude 1.5 since this is a level similar to vibrations caused by a heavy bin lorry going past, and would not pose a risk to buildings or people.
"(Magnitude) 1.5 would still be a conservative level,” Ben Edwards, specialist in engineering seismology at the University of Liverpool said at the same briefing.
The seismologists warned that raising the limit could lead to higher magnitude so called trailing events, which can occur after fracking has stopped, but said these would still likely be too small to cause any damage.
The government has said there are no plans to change the traffic light system.
"If we are to take forward what could be a very valuable industry, it is only right that we do so with the toughest environmental regulations in the world," Britain's energy minister told parliament earlier this month.
Fracking, or hydraulically fracturing, involves extracting gas from rocks by breaking them up with water and chemicals at high pressure.
It is fiercely opposed by environmentalists who say extracting more fossil fuel is at odds with Britain's commitment to reduce greenhouse gas emissions. They have also raised concerns about potential groundwater contamination.
The process also uses huge amounts of water, which must be transported to the site and local residents have complained about disruption from traffic and noise and a potential drop in the value of their homes.
The government, however, is keen to cut the country's reliance on imports of natural gas, which is used to heat around 80 percent of Britain's homes.
Both of the seismologists have advised Britain's industry regulator, the Oil and Gas Authority.
Cuadrilla is 47.4 percent owned by Australia's AJ Lucas, while a fund managed by Riverstone (LON:RSER) holds a 45.2 percent stake.
