The Use of Impact Chains to Describe Complex Cause-Effect Relationships Within a Systemic Multi-sectoral and Multi-hazard Risk Assessment

The occurrence of hazards and of their resulting impacts is characterised by complex interactions. Impact Chains (ICs) are conceptual models to streamline the analysis of such complex cause-effect relationships and to provide a structured framework for the comprehensive assessment of the related risks and of their components. ICs describe through an intuitive and graphical description the complex chain of cascaded impacts induced by possibly compounded natural and anthropogenic hazards. They can be built around current risks situation and extended through the identification of factors and elements related to a potential future situation. Moreover, they can be adopted to describe past disaster events through their integration with disaster forensic analysis. They are usually co-defined with domain experts in a participatory process and can be supported by desktop-analysis integrating knowledge from empirical evidence and scientific literature. Within the EU Horizon Europe “PARATUS” project, ICs are applied in four Application Case Studies (including the Caribbean, Romania, Istanbul, and Alpine areas) characterised by different hazard interactions and impacts on different sectors. Such ICs are developed though a standardized participatory methodology together with the local or regional authorities. Moreover, the analysis also encompasses several Learning Case Studies, focussing on past disaster events. The resulting ICs will be shared through the PARATUS platform to support the practitioners in the definition, analysis and quantification of the impact of multi-hazard events. This contribution focuses on the ICs methodology adopted within PARATUS while other contributions present the preliminary impact chains resulting from this.