GNGTS 2014 - Atti del 33° Convegno Nazionale

430 GNGTS 2014 S essione 2.3 A.Manicardi, M.Romani; 2009: La prevenzione del rischio sismico negli strumenti di pianificazione territoriale e urbanistica, Atti 28° GNSTS, Trieste. M.Romani e gruppo di lavoro “MS+CLE Emilia 2012”, 2013: Microzonazione sismica dell’area epicentrale dei terremoti emiliani di maggio-giugno 2012 8ord. 70/2012), Atti 32° GNSTS, Trieste. DAL 112/2007: Atto di indirizzo e coordinamento tecnico ai sensi dell’art. 16, c. 1, della L. R. 20/2000 per “Indirizzi per gli studi di microzonazione sismica in Emilia-Romagna per la pianificazione territoriale e urbanistica” . Deliberazione dell’Assemblea Legislativa della Regione Emilia-Romagna n. 112 del 2/5/2007. From the seismic microzonation to the reconstruction project: the case of Sant’Agostino Municipality, Italy A. Mantovani 1 , L. Martelli 2 , E. Melloni 3 , M. Romani 2 , R. Caputo 1,4 1 Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Italy 2 Servizio Geologico, Sismico e dei Suoli, Regione Emilia-Romagna, Bologna, Italy 3 Sportello Unico per l’Edilizia, Comune di Sant’Agostino (FE), Italy 4 Research and Teaching Centre for Earthquake Geology, Tyrnavos, Greece Introduction. On May 2012, a damaging seismic sequence affected a wide area of the eastern sector of the Emilia-Romagna region, between the boundaries of the Modena, Ferrara and Bologna Provinces. The sequence has been characterized by two main shocks, with M L ranging from 5.9 and 5.8, respectively (Fig. 1). The first occurred on May 20 at 02:03 UTC, with epicenter between Finale Emilia and San Felice sul Panaro (44°51’50”N, 11°14’31”E, h = 6.3 km), while the second occurred on May 29 at 07:00 UTC, 15 km south-west of the first shock, near Mirandola (Massa et al. , 2012). The causative faults of the two main shocks are segments of the Ferrara Arc thrust system, which is one of the three major arcs of blind, mainly north-vergent thrusts and folds representing the frontalmost portion of the Northern Apennines (Pieri and Groppi, 1981; Bigi et al. , 1982; Boccaletti et al. , 2004; Bonini et al. , 2014). These events, and in particular the first one, were responsible for a series of secondary ground deformation effects (Fig. 2), like widespread liquefaction phenomena and soil fracturing along abandoned river channels, that have affected especially the western sector of the Ferrara Province, causing severe structural damage to non-reinforced masonry and precast industrial buildings (Caputo and Papathanassiou, 2012; Galli et al. , 2012; GdL Liquefazione RER, 2012; Emergeo Woking Group, 2013; Papathanassiou et al. , 2012). Following the seismic sequence of May 2012, with the Ordinance 70/2012 the President of the Regione Emilia-Romagna predisposed the realization of seismic microzonation studies and analysis of the emergency limit condition for the most damaged municipalities included in the isoseismal VI (MCS) of the macroseismic field (Galli et al. , 2012). The purpose of the seismic microzonation studies is the characterization of a territory according to the local seismic response, i.e. the behaviour of the subsoil during a seismic event. In particular, these studies enable the identification and the delimitation of areas characterized by homogeneous behaviour distinguishing between i) stable zones, ii) areas susceptible of amplification of the ground motion and iii) areas subject to instability, such as landslides, liquefaction, and surface fractures. The distinction between areas characterized by different seismic hazard represents a necessary information for the local administrations in order to prevent and reduce the risk, as well as a fundamental support to the local urban planning so as to lead the choices to areas with a lower hazard and/or use of building constructions with a lower vulnerability to possible local effects. Among the municipalities concerned by the above mentioned Ordinance is that of Sant’Agostino, west Ferrara Province. Parallel to and complementary with the studies carried out by the Geological Survey of the Regione Emilia-Romagna limited to the urbanized areas, also the Earthquake Geology Team of the Ferrara University carried out aseismic microzonation study in the frame of a specific