Safe to raise limits for seismic tremors at UK fracking sites, experts say

New limit would be like a heavy bin lorry driving past, say seismologists

The UK could raise the limit at which seismic tremors force fracking activities to stop without compromising safety, experts have said.

Fracking at Cuadrilla’s Preston New Road site in Lancashire was halted a number of times last year when seismic activity exceeded limits set out in a traffic light regulation scheme.

Under the system work at fracking sites must be suspended for 18 hours if earthquakes above magnitude 0.5 are detected.

Brian Baptie, head of seismology at the British Geological Survey, told journalists that “existing regulations are quite conservative and are set at a level that is unlikely to be felt”.

The limit could safely be raised to magnitude 1.5 - described as similar to vibrations caused by a heavy bin lorry driving past - without posing a risk to people or buildings, he said.

“[Magnitude] 1.5 would still be a conservative level,” Ben Edwards, specialist in engineering seismology at the University of Liverpool added at a briefing.

Fracking is the process of extracting natural gas from rocks by breaking them with high-pressure water and chemicals.

Cuadrilla, the only company to have pursued the method so far in Britain, has complained the current seismic limits are too stringent.

The two seismologists did warn that raising the threshold could lead to so-called trailing events, which can take place after fracking has been stopped, occurring at a higher magnitude.

However, they added that these would probably still be too weak to cause 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,” energy minister Claire Perry told MPs earlier this month.

Raising the bar is strongly 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 fears of potential groundwater contamination.

The process also uses massive amounts of water which must be transported to the site. Residents nearby have complained about disruption from traffic and noise and a potential fall 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 about 80 per cent of Britain’s homes.

Both of the seismologists have advised Britain’s industry regulator, the Oil and Gas Authority.

Cuadrilla is 47.4 per cent owned by Australia’s AJ Lucas, while a fund managed by Riverstone holds a 45.2 percent stake.

Additional reporting by Reuters