Geological and geomorphological aspects related to the 2012 seismic sequence in the central-southern Po Plain (northern Italy)

Since May 16, 2012, a seismic sequence has affected the central-southern sector of the Po Plain, in the Modena, Ferrara, Bologna and Mantova provinces (Italy). The first main shock occurred on May 20 (Mw=5.9), followed by another two main shocks on May 29 (Mw=5.8). The subsurface of the epicenter area is characterized by several active compression north-verging faulted folds of the Apennines (known as "Ferrara Folds"), covered by marine and continental clastic deposits of the Po Plain. The most relevant surface effects caused by the strongest shocks was a 10-15 cm uplift of the epicenter area, detected by InSAR interferometry. Soil liquefaction phenomena are widespread and appear to be concentrated along alignments which can be followed for kilometers. At a detailed scale, more than 500 geologic and geomorphologic surface effects have been recorded over an area of about 700 square km. Hydrogeologic anomalies, such as strong water table fluctuations, emission of hot water from ground cracks and water wells have also been recorded all over the area affected.