The quake that struck at just after 4 a.m. Sunday was centered 35 kilometers (21.75 miles) north-northwest of Bologna at a relatively shallow depth of 10 kilometers (6 miles), the U.S. Geological Survey said.
Italian news agency ANSA, citing emergency services, said two people were killed in Sant'Agostino di Ferrara when a ceramics factory collapsed. Another person was killed in Ponte Rodoni do Bondeno.
In late January, A 5.4-magnitude quake shook northern Italy. Some office buildings in Milan were evacuated as a precaution and there were scattered reports of falling masonry and cracks in buildings.