The quake, centered about 12 kilometers away from the Weolsung nuclear power plant and a radioactive waste disposal facility, occurred at around 3:27 a.m.
A seismic trigger installed at the nuclear plant worked as the tremor hit the region, officials said.
The quake was felt by residents in Ulsan and Pohang as well as Gyeongju, they said.
"The building shook," a resident was quoted as saying.
reporter
Park Sae-jin
swatchsjp@ajunews.com
