GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 Automated StraHgraphic ReconstrucHon and SpaHalizaHon for Seismic Site Effect Analysis A. D’AgosHno 1 , A. Porchia 2 , G. Cavuoto 3 , F. Pavano 3 , M. Moscatelli 2 , G. Tortorici 2 , S. Catalano 1,2 1 Department of Biological, Geological and Environmental Sciences (DBGES) – Sec9on of Earth Science, University of Catania. 2 IGAG-CNR - Ins9tute of Environmental Geology and Geoengineering of the Italian Na9onal Research Council, Area Della Ricerca di Roma 1. 3 ISPC-CNR - Ins9tute of Heritage Science of the Italian Na9onal Research Council, Napoli. In the frame of the PRIN project "Mapping seismic site effects at regional and naConal scale – SERENA", we have developed a set of Python scripts within a GIS environment, aimed at reconstrucCng and spaCalizing straCgraphies. These codes represent an integral part of a workflow designed to divide the territory into straCgraphically homogeneous areas, providing representaCve straCgraphic columns for modeling and determining seismic amplificaCon factors. The code set consists of two scripts for straCgraphic reconstrucCons and a third script for their spaCalizaCon. The first unsupervised script operates on a raster base and generates straCgraphies based on a predetermined total thickness. The second supervised script works on vector cartographic bases and produces straCgraphies through individual steps. This procedure allows a progressive verificaCon of the straCgraphic column under construcCon. These first two scripts analyze the lateral contacts between the outcropping units, placing them in straCgraphic order based on a geometric posiCon index (Cesarano et al., 2022) and calculaCng the cumulated thickness. The third unsupervised script performs the spaCalizaCon by assigning the same ID to each unique reconstructed straCgraphic column. The final output is a 2D map made of polygons populated by the same column ID. In order to generate and spaCalize the straCgraphies, the employed raster or vector cartographic base must contain polygonal elements represenCng the Engineering-Geological Units – EGU (Technical Commission for Seismic MicrozonaCon, 2020). Each polygon must include a unique geometric posiCon index and a thickness value. The scripts were validated on the 428 km 2 wide Territorial Context (TC) of CariaC (Calabria, Italy) (Regione Calabria DGR 498/2019), since the EGUs had already been geometrically indexed (Fig. 1) and the straCgraphic columns manually reconstructed by Cesarano et al. (2022). In this study, the straCgraphic columns were represented in a matrix form. The