Geothermal plant ‘triggered earthquake’ in S. Korea

SEOUL: A rare earthquake in South Korea was triggered by the country’s first experimental geothermal power plant, a team of government-commissioned experts said yesterday.

The southeastern port city of Pohang was rattled by a 5.4-magnitude earthquake in November 2017 — the secondmost powerful tremor ever in the normally seismically stable South.

Dozens of people were injured and more than 1,500 left homeless — while a nationwide college entrance exam was postponed in an unprecedented move as authorities scrambled with recovery efforts.

A year-long governmentcommissioned study pointed to the geothermal power plant as the cause.

The plant works by injecting high-pressure water deep underground to tap heat from the Earth’s crust, but the process had produced micro-sized seismic activity as a result, said Lee Kangkun, who led the research.

“And as time passed, this triggered the earthquake in Pohang,” he added. “We concluded that the Pohang earthquake was a ‘triggered quake’. It wasn’t a natural earthquake.”

Pohang residents filed a lawsuit against the government after the quake, and following the assessment Seoul expressed its “deep regret”.

The geothermal plant — which was temporarily suspended during the study — will be “permanently shuttered”, the trade, industry and energy ministry said in a statement.

It cost around 80 billion won (US$71 million) to build and test operations began in 2016.