Enhanced geothermal systems marshal the Earth’s subsurface heat for electricity
Injecting fluid into the ground for geothermal power generation may have caused the magnitude 5.5 earthquake that shook part of South Korea on November 15, 2017. The liquid, pumped underground by the Pohang power plant, could have triggered a rupture along a nearby fault zone that was already stressed, two new studies suggest.
If it’s confirmed that the plant is the culprit, the Pohang quake, which injured 70 people and caused $50 million in damages, would be the largest ever induced by enhanced geothermal systems, or EGS. The technology involves high-pressure pumping of cold water into the ground to widen existing, small fractures in the subsurface, creating paths for the water to circulate and be heated by hot rock. The plant then retrieves the water and converts the heat into power.
Researchers examined local seismic network data for the locations and timing of the main earthquake, six foreshocks and hundreds of aftershocks to determine whether the temblors