Multi-hazard analysis of the Italian electric system

Abstract

<p>Italy is strongly exposed to geological hazards that affect the entire national territory causing casualties and damage to buildings and infrastructures. In this contest, the planning, maintenance and management of the electric system are strongly impacted by natural hazards. This study shows a national-scale classification of the areas exposed to natural hazards as a tool for risk management related to the power network.</p><p>The spatial distribution of the national electric grid elements (e.g. transmission lines, tower, and substations) was obtained by merging several regional and national databases, also accounting for the inaccuracy of the localization of the components (using positional mismatch method on regional milestones) and the voltage of each line. The vector database consists of about 72,000 kilometres of lines, 320,000 towers, and 4000 substations. The structures were overlaid with different datasets of natural hazard at national scale, including: alluvial hazard zones, landslide inventory, landslide hazard zonation, seismic hazard, earthquake-induced liquefaction hazard and avalanche map. In addition, the potential for earthquake induced landslides was obtained by combining landslide inventory and PGA (Peak Ground Acceleration) and the seismic hazard was improved by calculating the horizontal seismic coefficients for pseudostatic slope analysis, based on the national map of Vs30.</p><p>Through the combination of alluvial, landslide, seismic, avalanche and liquefaction hazards  a heuristic multi-hazard index (MHI) approach was developed. In order to assess the weights of the different natural hazards, a multi-criteria Analytical Hierarchy Process approach was  adopted, which allows a panel of experts to analyse the degree of influence of each natural hazard by pairwise comparisons. Landslides and earthquakes resulted to be the most important natural hazards, together with liquefaction (for transmission towers) and floods (for substations). The final MHI allows to highlight the most hazardous areas in Italy, especially concentrated in the NE of the Italian Alps (Friuli Venezia Giulia Region) and along the Central and Southern Appenine range.</p>