GNGTS 2014 - Atti del 33° Convegno Nazionale

tectonic structures that characterize the subsoil of the region and mainly associated with the recent activity (Late Quaternary) of the Ferrara Arc. In particular, it is possible to correlate the local high velocity gradient observed in the northern part of our profile to the Casaglia anticline, while the southern one likely corresponds to a deeper periclinal setting of the easternmost sector of the Mirandola structure (Fig. 1). The effects on the shallow velocity distribution caused by a secondary structure (here referred to the Casumaro structure) merge with those of the Casaglia anticline thus generating an apparently larger scale unique dome. By increasing the density of 1D velocity profiles along the investigated transect will likely improve the resolution of the pseudo-2D section thus allowing to distinguish the two structures. Conclusions and future work. The reconstructed velocity profile documents the possibility to detect the recent tectonic activity of buried structures underlying the alluvial Po Plain by means of low-cost geophysical surveys. Indeed the applied techniques does not need expensive equipment nor large teams. The passive seismic techniques allowed to measure in relatively short time numerous 1D velocity profiles down to a depth of 100-150 m (depending on the layout of the geophones). Accordingly, it is possible to carry out a sufficient number of such measurements to confidently interpolate a pseudo-2D section several kilometers-long therefore emphasizing the possible occurrence of lateral shear wave velocity variations corresponding to stratigraphic ones. The comparison with available seismic profiles for hydrocarbon explorations and particularly with the location of the major tectonic structures well documented at greater depths and affecting older rocks suggests that the shallow stratigraphic variations documented in this research are directly associated with a recent activity of the buried folds. This new methodological approach is being applied for investigating the shallow subsoil across similar structures east of Ferrara (profile 2 in Fig. 1). The data acquisition for this second profile are in progress and will be combined with a microgravimetric 3D survey specifically planned to include the profile. Aknowledgements. This study has benefited from funding provided by the Italian Presidenza del Consiglio dei Ministri - Dipartimento di Protezione Civile (DPC). This paper does not necessarily represent DPC official opinion and policies. Partly was also supported by the Province of Ferrara, DPC Unit and municipalities of Argenta, Ferrara, Bondeno and Comacchio. Fig. 3 – The pseudo-2D section (top) showing the shear-waves velovity distribution in the shallow subsoil (first ca. 150 m) as obtained by interpolation of several 1D ESAC and Re.Mi. profiles. Bottom: part of the geological section C-C’ from Boccaletti and Martelli (2004) running parallel to the section, ca. 7 km SE (see Fig. 1 for location). GNGTS 2014 S essione 1.2 121