GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.2 GNGTS 2023 An application for the town of Portici We, therefore, carry out a more detailed risk assessment for Portici, more closely investigating spatial interactions between overall seismic risk and social vulnerability. According to the latest census information, Portici has a residential population of about 55,400. It belongs to a medium-to-high seismicity class according to the Italian code classification of seismic zones (OPCM 3274, 2003), with a PGA value equal to 0,167 g for a mean return period of 475 years. For this more detailed analysis, the municipal territory is divided into sub-areas representing broad socioeconomic statuses of the residential population. The real estate observatory (Osservatorio del Mercato Immobiliare – OMI – in Italian) identifies homogeneous municipal areas based on maximum/minimum market and lease real estate values, expressed in euro per surface unit (square meters), type of property and state of conservation. Those areas are selected as the unit of analysis for this application. The SoVI is calculated for each subdivided unit (i.e., OMI zone) of the municipality, adopting the same approach used for the RI calculation (Figure 2). The necessary information for the SoVI estimation is derived from the most recent census data at the census tract level. All census tracts belonging to the same OMI zone are grouped through GIS software. Figure 2 –OMI homogeneous areas and their classification based on SoVI value. Each OMI zone is identified by an alphanumeric code that categorises the zone as Central (B), Semi-central (C) or Suburb (D). In line with the Risk-UE model leveraged as part of the RI calculation, which proposes Damage Probability Matrices for each vulnerability class and adopts macroseismic intensity as the ground-shaking intensity measure, we use the vulnerability models proposed by Rosti et al. (2021a) and Rosti et al. (2021b) for masonry and RC buildings, respectively. Moreover, these models are also officially adopted for the National Risk Assessment in Italy (Dolce et al., 2021). Buildings of other construction materials (e.g., steel, wood) represent only a negligible percentage of residential buildings (3%), so they are not included in the analysis. Information required for compiling the building inventory is mainly obtained from census data. The dataset of the interview-based CARTIS (CARatterizzatione TIpologico-Strutturale) form (Zuccaro et al. 2015) is used otherwise. CARTIS forms were used to survey ordinary building typologies in sub-areas called