No one was hurt in Sunday's 5.9-magnitude undersea quake that occurred 290 kilometers (223 miles) west of Athens.
Regional governor Dionysis Georgatos said Monday that roads had been reopened following landslides caused by the quake, but that several schools and public buildings remained closed as a precaution.
"We are used to earthquakes here. Fortunately, the damage was fairly limited," he said.
The Athens Geodynamic Institute said the 5.1 magnitude aftershock occurred at 5:20 a.m. (0220GMT) Monday, reports AP.
"Aftershocks are to be expected after an event like this, and some of them will be strong ... This is a very quake-prone area," the institute's research director Gerasimos Papadopoulos said.