
More than 100 aftershocks had been registered since Sunday's magnitude-5.9 quake, which killed seven people, the daily Corriere della Sera reported.
About 3,000 people spent the night in tents, sports halls or with friends and relatives.
Some people slept in their cars out of fear of more shocks, the broadcaster Rai reported.
A prison in Ferrara was evacuated as a precaution, Rai reported.
The epicentre of Sunday's quake was 36 kilometres north of Bologna. It had a depth of about 10 kilometres, according to the National Geophysical and Volcanic Institute.
Many schools in the affected area are to be closed Monday and Tuesday.//DPA