A light 4.9 magnitude earthquake on the Richter scale recorded at 20.34 (18.34 GMT) on Saturday was mostly felt in Ilia prefecture, southwest mainland Greece, according to the Geodynamic Institute of the National Observatory of Athens.

The epicenter was pinpointed at 17 kilometers south of the Ionian Sea harbor town of Kyllini and 10 kilometers southwest of the town of Andravida, both located in the northwest part of the Peloponnese province.

The National Observatory said the focal depth of the quake was 11.1 kilometers. The tremor caused minor unrest in the municipalities of Andravida-Kyllini, Pineios, Ilida, and Pyrgos, as well as in the adjacent island of Zakynthos in the Ionian Sea.

However, according to public broadcaster ERT, residents remained calm despite the tremor’s intensity, due to the relatively shallow focal depth.

According to statements made on ERT by the president of the Earthquake Planning and Protection Organization (OASP), Prof. Efthymios Lekkas, aftershocks may occur, while he added that there was no cause for concern.

“It is an extremely seismic region. When aftershocks start in this area, they usually continue for a few days due to their peculiarities. These aftershocks are usually of small magnitude, so we are not looking at very large magnitudes,” according to Prof. Lekkas, the head of the National Kapodistrian University of Athens’ Department of tectonic applied geology & Disaster Management.

Greece is a highly seismic country but much of the activity is reported in maritime regions, thus minimizing effects on the mainland. Last month the Dodecanese island of Rhodes, in the southeast Aegean, was hit by a 4.9-magnitude tremor, while two consecutive quakes shook a rural region in central Crete. However, both had the same epicenter, according to reports.