A Preliminary Report on the 2012 Seismic Sequence in Emilia (Northern Italy)

Since middle of May 2012 , an energetic seismic sequence is interesting the northern part of Italy and specifically a wide sector of the River Po Plain. The sequence has been dominated by two main events, namely a) a Mw = 5.9 occurred near Finale Emilia on 20th of May at a depth of 6.3 km, and b) a Mw=5.8 occurred near Cavezzo on 29th of May. The effects of the two main shocks can be mainly summarized as follows: - damages to the infrastructures (roads, pipelines)essentially because of the occurrence of liquefaction phenomena or soil failures; - damages to very old constructions (especially churches and bell towers – masonry and brickwork); - as for the very recent constructions, barns and industrial premises have shown a dramatic collapse). These constructions were mainly isostatic structures not designed to resist to any earthquake. The paper essentially deals with the following aspects - seismological aspects, mainly referring to the seismo-tectonic framework, the source mechanisms, and the comparison between the observed seismic motion and that expected on the basis of the National Map of Seismic Hazard; - identification and mapping of the soil failures (liquefaction) and induced damages with special emphasis on the geomorphological structures showing the presence of paleo – riverbeds; - description of the structural damages regarding the historical building and the modern industrial building; In conclusion the report will try to explain the reasons for the large damages observed in the case of both ancient and modern constructions