A light quake measuring 4.6 on the Richter scale was recorded at 06:02 on Sunday, according to the Geodynamics Institute of Athens' National Observatory.
The epicentre of the earthquake was located in the sea region 86 kilometres north-west of Athens and 33 klm north-west of Corinthos.
No damages or injuries were reported.
In statements to the Athens-Macedonian News Agency, Professor of Dynamic Tectonic Applied Geology and Natural Disaster Management of the National and Kapodistrian University Efthimios Lekkas expressed cautiousness as to whether this was the main earthquake.