Multi scale heuristic and quantitative multi-risk assessment in the Lombardy region, with uncertainty propagation

In this thesis, some methodologies for multi-risk assessment are presented, that can be applied to regional or local scale. At the local scale, the problem of uncertainty propagation in risk assessment is treated, testing different methodology for calculation. The work is organised in four parts: 1. Multi risk analysis at the regional scale in Lombardy (PRIM project, 2007). The methodology integrates information with different degree of accuracy into an indicator based approach, in order to develop a regional scale multirisk assessment and to identify “hot spot” risk areas for more detailed analysis. Eventually, the sensitivity of weights is investigated, and the effect on risk assessment of different individual attitudes and perception (i.e., expert, social, political, risk aversion). 2. Quantitative multi risk assessment (QRA) at the local scale on the hot spots, for lower Valtellina and the area of Brescia and lower Val Trompia, Val Sabbia, and Valcamonica. The methodology is based on the use of historical data and modelling to assess for each threat the expected number of casualties and the expected economic damage. 3. Quantitative risk assessment (QRA) for floods, earthquakes and industrial accidents in the area of Brescia (420 km2), with uncertainty propagation analysis. Frequency-damage curves were calculated. Three methods were 6 used and compared to calculate the uncertainty of the expected economic losses: Monte Carlo Simulation, First Order Second Moment approach, and Point Estimate. 4. Realization of a tool based on a system of indicators aimed at assigning a priority for the realization of new mitigation works, at the evaluation of efficacy of existent works, and at the comparison of different alternatives for the same risk scenario. Indicators are referred to the risk scenario, to the most recent and most significant event occurred in the analysed area, to the planning stage of the work, and to the technical characteristics of realization and maintenance of the work itself.