GNGTS 2013 - Atti del 32° Convegno Nazionale

An alternative approach. In order to tentatively overcome the problems of the PSHA procedure, the research group of the University of Siena, in collaboration with of the Regione Toscana ( Coordinamento Regionale Prevenzione Sismica) and Emilia-Romagna (Servizio Geologico, Sismico e dei Suoli) have proposed an alternative approach, extensively described in some publications (Mantovani et al. , 2011, 2012, 2013). The new approach mainly aims at minimizing the influence of the adopted procedure on the hazard maps, paying maximum attention to the available information, constituted by the macroseismic data set and the present knowledge on the ongoing tectonic setting in the study area. As concerns this last item, we have exploited the long experience and knowledge acquired by the Siena research team on the recognition of the geodynamic and tectonic setting in the Italian area (Mantovani et al. , 2009; 2010, 2012, 2013; Viti et al. , 2011, 2012; Cenni et al. , 2012) and the large set of information about the local structures provided by the above Regions (e.g., Boccaletti et al. , 2010; Martelli, 2011). To best fulfil the above conditions, we have chosen of not using statistical approaches for hazard assessment. It is assumed that each strong earthquake, even though remote and/or not confirmed by other successive or previous events, must anyway be taken into due account Fig. 1 – Map of I max values provided in the northern Apennines and Po Valley by the PSHA procedure (Gomez Capera et al. , 2010). 423 GNGTS 2013 S essione 2.3