GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 A systemaHc analysis at staHons of the Italian seismic network to test the role of local topographic effect. M. Ariano 1 , P.L. Fantozzi 1 , D. Albarello 1 1 Department of Physics Sciences, Earth and Environment, University of Siena, Siena, Italy The Italian seismic code (NTC18) provides indicaCons about the expected effects of some morphological configuraCons on the expected ground moCon during earthquakes. In parCcular, two main 2D morphologies are idenCfied as reference: cliffs and crests. Based on numerical simulaCons, the value of St is assumed to depend on the steepness of the cliffs and aspect raCo of the crest. A criCcal aspect of these esCmates is that the considered configuraCons are defined in terms of steepness angles and aspect raCos, without any scale indicaCon. Moreover, the considered morphologies are very schemaCc, and this prevents their simple applicaCon in the natural context: in most cases an expert judgement is necessary, and this makes the final esCmates potenCally controversial and difficult to validate on the basis of empirical observaCons. To face this problem, in the frame of the PRIN project “SERENA”, a procedure has been developed for the automaCc idenCficaCon of areas prone to morphological amplificaCon effects by following NTC18 prescripCons, based on the Digital Terrain Model. The proposed approach allows the full exploitaCon of topographical data at the maximum resoluCon available. Aper a first applicaCon to restricted areas, the proposed procedure has been applied at NaConal scale at the seismometric and accelerometric sites managed by INGV. The aim is twofold: first comparing outcomes of the new approach with the ones proposed by other Authors at the same sites, second to provide a sound basis of a coherent and reproducible esCmate of St values to be compared with possible empirical evidence. In the presentaCon, the results obtained about the first aim will be presented and discussed.