The quake, felt across much of the country including in the capital Seoul, struck at the shallow depth of nine kilometres (six miles) near the industrial city of Pohang at around 2:30 pm (0530 GMT), the Korea Meteorological Administration said.
Seven people were injured, Seoul’s public administration ministry said, but they warned that number could rise because the quake was shallow.
The Korean peninsula rarely has to worry about significant quakes.
But seismic activity is closely monitored because a spike in activity is often the first indication that North Korea has carried out a nuclear test.
The port city of Pohang is home to the headquarters of Posco — the country’s top, and the world’s fourth largest, steelmaker. No immediate damage was reported in the firm’s…