In order to provide a first hypothesis of regionalisation of the fragility curves for the masonry buildings of the municipalities with less than 50000 inhabitants in western Sicily, the data collected through the use of the Cartis form are used.

Subsequently, for the same municipalities, the data provided by the 2001 ISTAT census are analysed and compared with those derived from the CARTIS database. A disaggregation procedure of the ISTAT data is proposed which, assuming a homothetic distribution with the CARTIS survey data, based on the material and age distributions of buildings and number of floors. It allows to attribute with a statistical approach to the ISTAT data both the masonry typologies of the vertical structures and the stiffness of the slab, as well as other building characteristics considered significant in determining the seismic vulnerability of the built stock. The vulnerability of sub-types and archetypes is assessed through the use of the Heuristic Model recently proposed in Lagomarsino, Cattari and Ottonelli (2021 MELCO2021).

The fragility curves obtained from the Cartis database are then compared with those obtained in MELCO2021, by means of the characterization of the built stock through the ISTAT data, on the basis of the analysis of the vulnerability characteristics of the whole masonry buildings heritage in the Italian area. The data are disaggregated according to the construction period and the number of floors of the building.

Finally, the procedures are used to provide a first proposal of vulnerability assessment, and to describe the fragility curves of the residential masonry buildings in the municipalities of Western Sicily with a population below 50000 thousand inhabitants.