A moderate tremor rattled the island of Hydra in Greece's Saronic Gulf on Friday night.
The earthquake struck at 11.08 p.m. and was felt in Athens. Hydra is 85 kilometers southwest of the capital's main port, Piraeus.
The Athens-based Geodynamic Institute initially put its force at 5.4 on the Richter scale, but revised the figure upward to 5.6 to put back at 5.4 later. Its epicenter is said to have been located 28 kilometers off the southeastern coast of the island.
There were no initial reports of damages or injuries.