We planned a geophysical survey across some major tectonic structures affecting the subsoil of the eastern Po Plain, that possibly represent the seismogenic volumes of the above mentioned historical earthquakes. Our investigation consisted in a gravity survey carried out along a transect (Fig. 1b), ca. 170 km2 and oriented SSW-NNE, i.e. almost perpendicular to the regional trend of the buried structures belonging to the central sector of the Ferrara Arc. Along a profile centered around the studied transect, in order to investigate the shallow subsurface (say, down to ca. 150-200 m), several passive seismic measurements of ambient noise were also performed, whose results are described and discussed in a companion paper (see Mantovani et al., 2015).