Commenting three days after a strong 5.1-magnitude tremor shook the capital, Efthymios Lekkas, head of Greece's Earthquake Planning and Protection Organization, said on Monday that aftershocks of between 4 and 4.2 Richter were likely.
Speaking to Skai television on Monday, Lekkas said the seismic activity after Friday's quake was normal and that aftershocks of around 4 Richter would be "in the positive direction as this would fully confirm that we are in a phase of depressurizing."
The aftershocks could happen up to a week from now, Lekkas added, noting that it might not be noticed by many but will be felt by those in high buildings.
As for the Parnitha fault line that triggered both the 5.9-level quake that struck the capital in 1999, killing scores, and Friday's temblor, Lekkas said that three quarters of the fault line was activated in 1999 and the rest last week.
"Now we know that the fault line cannot produce another strong earthquake."