The first earthquake, registering magnitude 6.1, struck in the Emilia-Romagna region, about 36 kilometres (22 miles) north of the city of Bologna, on 20 May at 04:03 local time (02:03 UTC).

Information from hydrocarbon exploration demonstrates that the area is underlain by a series of active thrust faults and related folds, some of which have been detected from anomalous drainage patterns.

These blind thrust faults are roughly WNW–ESE trending, parallel to the mountain front, and dip shallowly towards the south-southwest.

[20] Initial reports after the 20 May shock listed seven dead, including four workers at a factory in Ferrara,[1] and about 5,000 people left homeless.

[23] Half of a clock tower in Finale Emilia dating from the 13th century (known as the torre dei modenesi) fell down in the mainshock and the remaining part collapsed completely during an aftershock later that day.

[24] Production of Grana Padano and Parmigiano-Reggiano hard cheeses was badly affected; approximately 300,000 wheels, with an estimated value of €200 million, were destroyed.

Stefano Gresta, president of the National Institute of Geophysics and Volcanology, deemed it "unacceptable that modern constructions such as warehouses and industrial sheds have collapsed in an earthquake which was strong, but not exceptional".

[26] The area was not included in seismic hazard maps until 2003, when, after a reassessment, it was classified as "medium risk", with a 10% likelihood of such an earthquake in the next 450 years.

A local union representative has demanded an investigation to determine who was responsible for permitting the companies to resume operations.

[30] An aftershock on the 3 June was felt throughout Northern Italy and caused the collapse of the 18th century clock tower in Novi di Modena, already imperilled by the earthquake of recent days.

[31] The earthquake damage in Emilia "could exceed 4 billion" according to the vice-president of Confindustria Emilia-Romagna, Gaetano Maccaferri, who released these figures in testimony before the Senate Committee on Industry.