Experts have told NCE that seismic events caused by shale gas drilling should not necessarily be a cause for alarm, following last week’s report into Lancashire’s two earthquakes.
The report, commissioned by developer Cuadrilla, concluded that it was “highly probable” that two seismic events — one of magnitude 2.3 in April and another of 1.5 in May — near Blackpool in Lancashire were caused by the firm extracting shale gas using the highly controversial hydraulic fracturing.
However, experts told NCE, drilling underground often caused seismic activity.
University of Edinburgh professor Stuart Hazeldine said minor tremors due to shale gas drilling are to be “expected”, and added that there was no damage to infrastructure. Hazeldine said that in the past coal-mining often produced significant seismic activity. However, shale gas is unlikely to create similar problems from subsidence because much less material is being extracted from the ground, he added.
University of Manchester professor of structural geology Ernie Rutter said that the area Lancashire area where the drilling took place is one of the most seismically active in the UK. According to the British Geological Survey earthquakes of magnitude 3 to 3.9 occur around three times a year in the UK. He added that shale gas drilling induces earthquakes in places that are more seismically active.
In the US, policy institution Center for Strategic and International Studies senior vice president Frank Verrastro said there were only three instances of seismic activity due to shale gas drilling there – in Texas, Arkansas and Oklahoma – even though shale gas extraction is much more common than in the UK. Verrastro added the seismic activity caused by shale gas drilling “wasn’t a major concern”.