The body of an 83-year-old man has been recovered from the ruins of a building near Teramo that collapsed due to a combination of heavy snowfall and the recent tremors.
Another man is missing and feared dead following an avalanche near L'Aquila.
The search for the 60-year-old man, who was buried under metres of snow at Campotosto, was called off Wednesday night after hopes of reaching him faded.
Three livestock farmers have also been reported missing, after friends were unable to contact them via mobile phone.
Another 12 farmers who had been reported missing have been tracked down.
A resident of the Abruzzese village of Pizzoli gave a dramatic cellphone report of the situation after the quakes hit the snowbound town:
"We're in the street, submerged in snow and we can't even flee. The cars can't move because of the snow. There are continuing quakes and people are screaming in the streets. I'm vainly trying to reach my mother who's in a building in Montereale.”
The first quake occurred at around 10:25 am and rocked the regions of Lazio, Abruzzo and Le Marche.
Another two tremors followed at 11:14 am, and 11:26 am.
The nightmare continued, as a fourth quake shook the area shortly after 2:30 pm.
According to initial estimates by the National Institute of Geophysics and Vulcanology (INGV), the first and third earthquakes were magnitude 5.3, and the second tremor was slightly stronger at magnitude 5.4.
Experts at the INGV stated that the occurrence of four quakes above magnitude 5.0 in the space of three hours is unprecedented.
“[The cluster of quakes] is a new phenomenon in recent history for the modalities with which it manifested itself," seismologist Alessandro Amato said.
The epicentres of all four quakes were in the province of L'Aquila, in Abruzzo, while the tremors were felt as far away as Ravenna in the north and Foggia in the south.
Parts of some structures have collapsed following the tremors, including the bell tower of the Sant'Agostino church in Amatrice, a town largely destroyed by the August earthquake.
Some Rome metro stations were evacuated as a precautionary measure and services suspended, although trains have started running again on the A line.
Rome Mayor Virginia Raggi declared on Wednesday that there is no cause for alarm in the capital.
"In agreement with the prefect's department, which has contacted the fire brigade's operative centre, [I can say] there is no reason for alarm in the city," Ms Raggi said on her Facebook page.
The young mayor added that she had not decided to close the city's schools, but that checks would be run to make sure school buildings are fit for use.
Civil Protection Chief Fabrizio Curcio said that assessing the situation after the latest series of earthquakes was difficult, due to heavy snowfall in many areas.
"The situation is quite complicated," Mr Curcio told Sky television.
"We are receiving reports from all over the nation. Obviously, the quake was felt clearly all over the centre, as far as the capital.
"At the end of the checks we'll be able to say whether we've had particularly difficult situations or not. It has been snowing without stop in that area for hours and it will continue to do so for the next few hours.”
With ANSA
