GNGTS 2013 - Atti del 32° Convegno Nazionale

The referring borehole station makes possible the estimation of the site amplifications for those sites with instrumentation still operating in 2013. The reference methods allow an easier identification of the frequency of resonance, since peaks appear sharper than those displayed by single-station methods (both H/V on ambient noise and earthquakes). In particular, amplification in the range of 0.5-1 Hz, 1.8Hz and 2.8 Hz, are recognised in all the sites, even though with different levels. This suggests it is reasonable to consider the resonance frequencies and the values of amplification obtained by the single-station spectral ratio of earthquakes (EHV) as constraining values for the amplification of the site, where it was not possible to estimate an amplification factor (due to the lack of synchronous registrations with the reference site). The recordings of the temporary network deployed in Ferrara area soon after the main event of May, 2012, were compared with the prediction of ground motion (GMPE and ShakeMaps). The analysis show that the theoretical data are in agreement or slightly overestimated compared to the observed data. Two sites (OG003 and OG004), show major discrepancies, probably related to soil liquefaction phenomena. Acknowledgements. This research has been supported by the Dipartimento della Protezione Civile: Project S2, ProCiv-INGV (2012–2013). The authors wish to thank the Ferrara University colleagues R. Caputo, N. Abu-Zeid and G. Santarato for support in OGS temporary network deployment and our colleagues G. Durì, M. Bertoni, E. Del Negro for support in Casaglia site. References Andrews D.J.; 1986: Objective determination of source parameters and similarity of earthquakes of different size . In: Boatwright J., Scholz C.H. and Das S. 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