People in Turkey's largest city, Istanbul, felt the rumble of a 4.4 magnitude earthquake on Sunday.
Istanbul is on the edge of the Sea of Marmara, where the earthquake was centred. No damages or injuries were immediately reported.
But Turkey has had serious earthquakes in the past. About 18,000 people died in a pair of earthquakes in northwestern Turkey in 1999.
Earthquakes are frequent in Turkey because the country sits on faultlines.
With files from The Associated Press