By Agence France-Presse
The earthquake occurred 14 kilometres (9 miles) southeast of Bodrum, one of the busiest tourist resorts on the Turkish Aegean, at a depth of 10 kilometres, USGS said.
Several residents fled their homes for fear of buildings collapsing, according to NTV, a Turkish television channel.
Turkey, situated on major seismic faultlines, is regularly hit by earthquakes. The Aegean coast has suffered several quakes above 5-magnitude since the start of the year.
Last month, two foreigners died and more than 100 people were injured on the Greek island of Kos when an earthquake shook popular Greek and Turkish holiday destinations in the Aegean Sea.