Friday, April 27, 2018

Fracking Dangers

One of South Korea’s largest earthquakes on record may have been caused by hydraulic fracturing – or fracking – according to a study. A team of researchers from the University of Glasgow, ETH-Zurich in Switzerland and GFZ-Potsdam in Germany analysed data from seismographic stations as well as satellite data to locate where the main shock and 46 aftershocks of the quake occurred.

For decades, the Korean peninsula has seen almost no seismic activity. A magnitude-5.5 earthquake hit the south-eastern city of Pohang on 15 November, injuring at least 70 people, temporarily displacing hundreds, and causing millions of dollars of damage.  Residents and researchers have questioned whether the quake could be connected to a geothermal plant – the country’s first – less than 2km (about 1 mile) away.

 The main shock occurred within 1.5km of where plant workers had been pumping thousands of cubic metres of water into the ground, creating or opening fractures in the rocks to enable water to pass between boreholes. The last of those injections was about two months before the quake. They also found that the main shock and aftershocks all occurred at depths of between 3 and 7km, which are shallow compared to previous quakes in that area, but similar to the depths at which the water was being injected.
“It would be a very a remarkable coincidence if this earthquake were to be unrelated to the activity at the site, given that it occurred so close to it,” said Robert Westaway, a senior research fellow at Glasgow university’s school of engineering, and one of the paper’s co-authors. “My own personal view is that it is highly likely there is a connection...“No one ever thought that injecting such a small amount of water could lead to such a large earthquake,” Westaway said.

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