The quake occurred at around 2:29 p.m. some 9 kilometers north of Pohang, the Korea Meteorological Administration said. The quake was felt across the nation, including Seoul about 370 km away from the port city.
Samsung Electronics Co. said it is currently looking into the situation at its chip production facilities located in Gyeonggi Province. The company is the world's No. 1 manufacturer of computer chips.
South Korea's No. 2 chipmaker SK hynix Inc. said its lines located in Gyeonggi and North Chungcheong Province are all operating normally.
Officials from the companies said while some production machines ceased operation automatically after sensing the earthquake, they immediately resumed normal operation.
LG Display Co. also said some of its facilities located in Gumi, west of Pohang, halted operation temporarily, but work started again after inspections.
South Korea's top steel maker POSCO, based in Pohang, said it experienced no damage from the earthquake so far. The company is conducting inspections to ensure safety, it added.
Samsung and SK hynix experienced temporary suspension of chip production in September last year when a more powerful quake struck near Gyeongju south of Pohang. (Yonhap)