ATHENS — Greek authorities say an earthquake with a preliminary magnitude of 5.4 has struck off the western islands of Zakynthos and Cephalonia, but no damage or injury has been reported.

The Athens Geodynamic Institute said the undersea temblor occurred at 10:36 a.m. (0736 GMT) about 57 kilometers (35 miles) southwest of Lixouri on Cephalonia in the Ionian Sea. It was felt across much of western Greece.

The Fire Service said it had no reports of damage or injury from the quake.

The region is one of the most earthquake-prone in Greece, which in turn is in one of the world’s most seismically active areas. But following destructive quakes in the 20th century, buildings in the Ionian islands are constructed using strict seismic safeguards.

While earthquakes in Greece are common, severe damage and deaths are not. In 1999, a quake near Athens killed 143 people.

Navagio beach on Zakynthos closed after rockfall

Authorities on the island of Zakynthos have closed Navagio Beach, a popular tourist destination that is famous for its signature shipwreck, after the 5.4-Richter earthquake earlier on Thursday caused large rocks from the surrounding cliffs to come loose and fall into the bay.

The rocks fell into the sea, fortunately without damaging boats sailing nearby.

The Zakynthos coast guard has forbidden visitors from alighting on the beach by boat and also blocked access by road, for fear of more rockfalls.