FRACKING may have caused an earthquake which caused tens of millions of pounds in damage to a South Korean city, Scottish experts say.

Around 100 people were injured when the 5.5 magnitude quake struck near Pohang in November. A seismic faultline was initially thought to be to blame but local agencies later case doubt over the cause.

In a new paper published today in the journal Science, researchers from Glasgow University, together with colleagues in Switzerland and Germany, suggest human industry may be to blame.

The study shows the mainshock and largest aftershocks happened within 2km of a fracking site.

Thousands of cubic metres of water had been injected under pressure into boreholes around 4km beneath the site in the months before the quake, which happened at depths of just three to seven kilometres below the surface – far above those that moved the earth in previous quakes.

The largest tremors also happened within 1.5km of an event induced in April that year during underground operations.

Dr Rob Westaway of Glasgow’s University’s School of Engineering said the quake was “about 1000 times larger, in terms of the energy released, than would be expected” given the volume of water funnelled into the land. He added: “The fault was no more than a few hundred metres from the injection points, making it likely, in my view, that it was caused by the fluid injection.

“Regardless of whether this earthquake is eventually shown to have been induced or not, it illustrates the assessment of the risk of induced seismicity for deep geothermal projects is challenging, because significant faults near an injection site cannot be identified or imaged with certainty.”