Police and the Fire Service said it had received no reports of injuries of damage on Psara or other nearby islands.
The undersea quake occurred at 3:43 a.m. (O143GMT), 200 kilometers (125 miles) northeast of Athens, the Greek Geodynamic Institute in Athens said.
The U.S. Geological Survey gave the quake's magnitude as 5.0.
Russia will complete the operation of the Soyuz booster rocket already in 2019. It goes about the booster, which Russia currently uses for manned space flights to the International Space Station