GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.2 GNGTS 2023 the entire national territory. The research would meet the need for an official national reference map providing co-seismic site ground acceleration at the scale of interest of land use planning and bridging the information gap now existing among the urbanized areas covered by Seismic Microzonation studies. The project aims at defining a multidisciplinary procedure for a multiscale mapping of the local seismic hazard of Italy, combining the regional estimates with site effects expected during earthquakes. The key elements are: full exploitation of geological/geomorphological data, extensive numerical modelling and empirical testing of local hazard estimates. In particular, the proposed study deals with the regional scale analysis and classification of the landscape and the related changes of the geological-technical properties of the near-surface stratigraphic configurations (GeoMorpho-Stratigraphic Units - GMSUs) that can affect local seismic hazard, through the different morpho-structural domains of the Italian Peninsula. The definition of the GMSUs s will be obtained by combining an automated landscape classification procedure, lithostratigraphic constraints from field geological studies, instrumental signatures from geophysical investigations and geotechnical parameters. The basic idea is using the distinct GMSUs to spatialize geophysical/geotechnical data and the outcomes of numerical modelling of the ground amplification based on the local stratigraphic and topographic features. Distinct parameterizations will be determined for each GMSUs and used to feed simplified numerical models to obtain synthetic hazard indicators suitable for land planning and risk evaluations. Outcomes will be managed in the frame of a coherent probabilistic approach to bound relevant uncertainty as a function of data locally available. Outcomes will be tested by considering accelerometric data widely available at regional scale and representative site-specific analyses. The work plan includes seven work-packages (WP): ● WP1: Data gathering, management and sharing ● WP2: Identification and lithostratigraphical characterization of GMSUs ● WP3: Seismostratigraphical characterization of GMSUs and estimate of stratigraphic amplification effects ● WP4: Identification of morphological configurations and estimating their impact on seismic amplification effects ● WP5: Geotechnical characterization of GMSUs and evaluation of the potential seismoinduced instability (landslides and rock falls) ● WP6: Empirical testing of outcomes ● WP7: Project monitoring and dissemination The outcomes will be released in a geodatabase showing the classification of the entire national territory, according to different characterized and modelled GMSUs, and a grid of regularly spaced nodes where punctual values of the estimated local seismic hazard, calculated for different return periods, are plotted.