The controversial new drilling operation for natural shale gas in Lancashire has been suspended following a second earthquake in the area that may have been triggered by the process.
The British Geological Survey is claiming there may be a link. How established is the science behind this?
Earthquake experts from the British Geological Survey said that the 1.5 magnitude quake last week was similar to a 2.3 earthquake in April in the same area and that both may be linked to the experimental fracking for shale gas at Preese Hall on the Fylde coast.
Brian Baptie from the BGS:
"We had a couple of instruments close to the site and they show that both events were close to the site and at a shallow depth.
"The timing of these two events in conjunction with the ongoing fracking at the site suggests that they may be related." He added: "It is well-established that drilling like this can trigger small earthquakes."
So how well established is it? And can it trigger larger earthquakes, perhaps not in the UK but in areas of greater geological sensitivity?