Factories, warehouses and churches collapsed after the 5.8 magnitude quake, leaving about 14,000 people homeless in the Emilia Romagna region north of Bologna.
The tremor was felt as far north as Austria. Dozens of aftershocks also hit the area, some registering more than 5.0 in magnitude.
The latest quake terrified many of the thousands who have been living in tents or cars since the 20 May quake left them homeless.
“I was shaving and I ran out very fast, half-dressed,” a resident of Sant’Agostino, one of the towns devastated in the quake earlier this month, said.
Today’s quake struck just after 9am with an epicentre about 25 miles northwest of Bologna, according to the U.S. Geological Survey – just miles from where the 6.0-magnitude quake that killed seven people last week was centred.
Government undersecretary Antonio Catricala said at least 15 people were killed, 200 injured and seven more were missing. The number of homeless swelled by several thousand, to a total of 14,000, he said.
While today’s quake was about 100 times less intense than the one on 20 May, its death toll was more than twice as high. The dead included workers killed by collapsing factories and warehouses.
In the town of Mirandola, near the epicentre, the Church of San Francis crumbled, leaving only its façade standing. The main cathedral also collapsed.
Sant’Agostino’s town hall, already badly damaged from the earlier quake, all but collapsed when the latest tremor struck.
Italian prime minister Mario Monti pledged the government would do “all that it must and all that is possible in the briefest period to guarantee the resumption of normal life in this area that is so special, so important and so productive for Italy”.
Many victims of the new quake, like those of the one nine days ago, were at work in huge warehouses that collapsed. One person was killled inside a machinery factory in Mirandola.
Labour minister Elsa Fornero suggested the destruction to buildings was out of proportion, considering the magnitude of the quake.
“It is natural that the earth shakes. But it is not natural that buildings collapse,” she said.
Tall buildings and schools were evacuated as far away as Milan as a precaution before people were allowed to re-enter. Train lines connecting Bologna with other northern cities were halted while authorities checked for any damage.
When today’s tremor hit, Mr Monti was meeting emergency officials in Rome to discuss the impact of the earlier quake, which struck in the middle of the night and left at least 7,000 homeless.
The 20 May quake was described by Italian emergency officials as the worst to hit the region since the 1300s.
In addition to the deaths, it knocked down a clock tower and other centuries-old buildings and caused millions in losses to a region known for making Parmesan cheese.
It is not clear why two large quakes have occurred in the same month, said Jessica Turner, a geophysicist with the US Geological Survey.
The basic driver of the activity is the same kind of geological shifting that produced the Alps, she said.
Prior to last week, the last earthquake in the region with a similar magnitude was in 1501.