A UK fracking site has halted operations after seismic activity was detected.  This happened only about a week after fracking resumed in the country for the first time since 2011.

Cuadrilla Resources confirmed it paused work its Preston New Road site in Lancashire because of the microseismic event, which was measured at a magnitude of 0.4 and within the limit allowed by UK authorities under the "traffic light" system if seismic warnings.  If an event exceeds 0.5 on the local magnitude scale, it is defined as a "red alert", and the frackers must shut down.  Any activity from 0.0 to 0.5 is defined as an "amber alert" and allows firms to proceed with caution.

But campaigners says even that was too much.

"It is only what we've been expecting as it is an undisputed consequence of extreme energy extraction," said Gail Hodson, of the campaign group Frack Free Lancashire.  "It highlights the fact that all the regulation in the world, even if it was gold standard, cannot stop seismic activity.  The traffic light system was cooked up as a salve to try to reassure the public and those reassurances have come to nothing.  The government should place a ban on fracking with immediate effect."

That's exactly what happened in 2011 when fracking caused a seismic event measuring magnitude-2.3 very close to a shale gas fracking site.  AN investigation found that it was highly probable that the fracking operation caused the tremors.

The 0.4 event wasn't powerful enough to detect on the surface, but the British Geological Survey said it was the sixth small temblor detected since fracking resumed last Friday.