GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 2.1 431 project financed by the local administration. Accordingly, all investigation activities have been carried out in a complementary and synergistic way in order to provide the local Administration a refined survey of the entire territory. The technical references for the realization of this study are described in the specific attachments of the Ordinance 70/2012 which derived mainly from the regional guidelines, “Indirizzi per gli studi di microzonazione sismica in Emilia-Romagna per la pianificazione territoriale e urbanistica” approved with the Deliberation no. 112/2007 of the Legislative Assembly of the Regione Emilia-Romagna (DAL 112/2007), and national ones, “Indirizzi e criteri per la microzonazione sismica” approved by the Civil Protection Department (Gruppo di lavoro MS, 2008) (Martelli and Romani, 2013). Geological and geomorphological framework. The municipal area of Sant’Agostino is characterized by a largely flat morphology, with variable altitudes ranging from 8 m to 16 m a.s.l. The only relief is represented by the levees of an abandoned reach of the Reno River aligned in a NE-SW direction, and from that of the active Reno River delimiting the southern sector of the administrative boundary. The abandoned branch of the Reno River was active from the MiddleAges until the XVIII century (Cibin and Segadelli, 2009). In particular, following the disastrous flooding events of the 1451 and 1457 (Frizzi, 1848), the Reno River was artificially channeled running between Cento and Pieve and it soon started to rapidly prograding several kilometers in just few years. Therefore, the course was more or less artificially extended towards Sant’Agostino and Vigarano Mainarda, where it was left to freely flood the area southwest of Ferrara in order to infill this natural depression. This hydrographic setting persisted for about 300 years and geographical stability allowed the establishment of new settlements like San Carlo and Mirabello. Until the late XVIII century the Reno River was unable to reach the Adriatic Sea and also to directly flow into the Po River, so wide inland marshes and lakes were formed. The depositional evolution of the territory was marked by the ineffective construction Fig. 1 – Emilia seismic sequence of the 2012. The red and orange stars are referred respectively to the main shocks of May 20 and 29. The black stars show the location of the major aftershocks (Mw ≥ 5.0), while the dots blacks show the events with Mw ≥ 1.5. The blue triangles show the observed liquefaction (Caputo and Papathanassiou, 2012; EMERGEO Working Group, 2012; WG Liquefaction RER, 2012]. Limits of the Sant’Agostino Municipality are indicated.