Magnitude 4.8 earthquake hits South Korea

A magnitude 4.8 earthquake has hit South Korea, according to the US Geological Survey.

The epicentre of the quake, which hit about 7am today AEDT, was near the coastal city of Pohang - about 170km south-east of the Winter Olympics site of Pyeongchang.

There were no reports of casualties or damage.

The Korea Meteorological Administration said the quake was an aftershock from a magnitude 5.4 earthquake that struck Pohang in November, the Yonhap news agency reported.

Mobile phone users in the Olympic village with an appropriate app received an emergency alert in Korean.