An earthquake of magnitude 4.7 hit South Korea's Daegu at 1.33 am on Saturday night.
The quake happened about 170km from the Winter Olympics site with tremors felt across the country.
The epicentre is 36.08 degrees north latitude and 129.33 degrees east longitude. The depth of the earthquake is 14km.
The Meteorological Agency have said this is an aftershock of the 5.4-magnitude earthquake that occurred in Pohang on November 15 last year.