GNGTS 2022 - Atti del 40° Convegno Nazionale

322 GNGTS 2022 Sessione 2.2 the entire Italian territory (http://esse1-gis.mi.ingv.it) . For each investigated zone where numerical simulation of site response are planned, the closest node of the grid is selected to obtain the parameters of the scenarios satisfying the criterion indicated for the stage 2). The results of the disaggregation analysis are reported as fractions of the contribution to hazard for combinations of linearly spaced intervals of magnitude (M) and distance (D), thus we select the smallest number of M/D interval combinations whose cumulative contribution to hazard exceed 2/3 of the total (Fig. 1). All the combinations within such intervals are considered representative of scenarios among which to search for accelerograms that could be used as seismic inputs of site response simulations. Fig. 1 - Example relative to Altamura, showing the selection of the scenario parameters for which accelerograms are considered in the following stage of the proposed procedure, in search of those accelerograms whose SA values match the local design spectrum. Red dots represent the M/D combinations taken into consideration in the search for accelerograms from the available databases. Regarding the real records to be extracted at the stage 3) from existing databases, in our tests we have used the RexelWeb tool (Sgobba et al. , 2021) linked to the databases ITACA (Russo et al. , 2022) and ESM (Luzi et al. , 2020), which provide Italian and European accelerograms. In addition to RexelWeb, we have used also the international database CESMD (www.strongmotioncenter.org) . These web resources allow to extract accelerograms recorded within a selected distance interval from the location of events with magnitude falling in a selected range and caused by a predefined type of fault. Thus, the results of the analysis carried out at the stage 2) are used to define the upper and lower bound of magnitude and distance to be used in the accelerogram selection.