A PROMETHEE Multiple-Criteria Approach to Combined Seismic and Flood Risk Assessment at the Regional Scale  
[PERSON]  
1 Department of Engineering, University of Ferrara, 44122 Ferrara, Italy; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Environmental and Prevention Sciences, University of Ferrara, 44122 Ferrara, Italy; [EMAIL_ADDRESS]  
[PERSON]  
3 Faculty of Civil Engineering, Architecture and Geodesy, University of Split, 21000 Split, Croatia; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Environmental and Prevention Sciences, University of Ferrara, 44122 Ferrara, Italy; [EMAIL_ADDRESS]  
[PERSON]  
1 Department of Engineering, University of Ferrara, 44122 Ferrara, Italy; [EMAIL_ADDRESS]  
Footnote 1: email: c.c. The choice to adopt a multi-risk analysis approach has the potential to play a fundamental role in increasing urban resilience, an essential factor for sustainable development, enabling cities to prepare, respond, and recover when hit by catastrophic events, and therefore prevent or contain economic, environmental, and social losses [1]. However, performing a multi-risk analysis with the tools and methodologies available today raises numerous challenges and difficulties [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]. For instance, an updated analysis of multi-hazard aggregated risk for infrastructures considering multiple potential threats has recently been proposed in reference [5]. Risk assessment is indeed carried out through independent procedures that adopt different estimation metrics. This makes comparisons difficult and precludes considering correlations or cascading effects [11]. On the contrary, the Multiple-Criteria Decision Analysis (MCDA) technique is a promising approach in multiple-hazard risk analysis, even if this route has been scarcely explored to date [21, 22, 23, 24]. To pave the way for sustainable land-use plans and risk-mitigation strategies, we must analyze, quantify, and, especially, compare all concurrent risks [25]. To date, single-risk assessment is generally performed by means of independent procedures, whose results cannot be compared. The purpose of this paper is to devise an approach for the qualitative assessment of combined risks at the regional scale. In particular, the objective is to jointly analyze the flood and seismic risk for the Ferrara province area. The proposed approach is based on the suitable use of the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE), a Multiple-Criteria Decision Analysis technique [26, 27, 28, 29]. The province of Ferrara is in a flatland area in the northern part of Italy. Historically, it has been mainly hit by floods and seismic events. Though floods are exogeneous processes, whereas earthquakes are exogenic, we assume flood and seismic hazards to be the two relevant hazards for determining a priority list. This priority list is meant to be useful to stakeholders and public agencies called to rapidly implement investment plans aimed to prevent economic and life losses and foster the coping capacity of communities to manage the adverse conditions induced by natural disasters. Particularly, the present objective is to prioritize this among the different municipalities. Therefore, the adopted level of observation is at the scale of the area included within each municipality. Assuming the municipalities of the province of Ferrara as the alternatives of the multiple-criteria analysis, the proposed approach defines a priority ranking among all the alternatives. The outcome is represented by qualitative risk maps. These maps are useful tools for stakeholders involved in community management and risk prevention. Among the Multi-Risk Methodologies applied in Italian territories, we recall here the works by [PERSON] et al. [23, 24] for the assessment of the impact of sea-level rise, coastal erosion, and storm surge induced by climate changes in coastal zones in North Italy.