Seismologist Efthymis Lekkas, who heads Greece’s Organization of Earthquake Planning and Protection (OASP), told state broadcaster ERT that Tuesday’s 6.3 magnitude quake south of Ierapetra on the island of Crete was the main one.
However, he noted that experts will have to wait two days for the post-earthquake sequence.
He also noted that it did not come from the same epicenter as that in Arkalochori, in the region of Iraklio, on September 27.
The research director of the Geodynamic Institute, Gerasimos Houliaras, said a similar earthquake of the same magnitude or slightly smaller is very likely.
Meanwhile, the Civil Defense Ministry dispatched disaster response units to Crete to help emergency services.
Teams of police, firefighters and other responders were active on the island identifying damaged buildings and infrastructure and any possible casualties from the powerful quake that set thousands of people scurrying from their homes.
According to the ministry, there were no reports of injuries, neither on Crete nor on the nearby islands that also felt the tremor.
The coast guard was also mobilized to respond in the event that the undersea quake triggered a tsunami.
Damage was reported, particularly in the region of Sitia in southeastern Crete, while a small church has collapsed on the outskirts of the village of Xirokambos.
There were also reports of rockslides in many parts of the island.