IMPROVER D2.1 Methodology for identifying hazard scenarios to assess  the resilience of critical infrastructure

Critical infrastructure is exposed to a wide range of hazards, capable to disrupt its operations in various degrees. This raises the question of which hazard scenario an operator shall use to assess the resilience of their critical infrastructure asset. Various techniques aiming to prioritize the various risks are commonly used in the literature. This study proposed an 8-step methodology, which aims to rank the risks of pre-defined hazard scenarios by eliciting the opinions of the stakeholders through a structured expert elicitation technique termed paired comparison. The novelty of the proposed technique is its ability to quantify the degree of disagreement regarding the ranking order of the scenarios and thus to capture the uncertainty associated with these risks. The proposed methodology has been applied to four living labs, namely: the Oresund region, the port of Oslo, the A31 Highway in France and the potable water network in Barreiro. The applications aims to rank scenarios of natural and operational hazards according to their disaster- and emergency-risk. Despite the small number of participants, the results provide an excellent basis for further discussion regarding the most likely disaster or emergency risk scenarios. For most living labs, the ranking of the hazards using paired comparison was successful in identifying the scenarios associated with the highest risk. Overall, ranking the natural hazards according to their disaster- or emergency-risk has been associated with a higher degree of consensus than the ranking of the operational hazards reflecting on the higher complexity and perhaps the limited understanding of the later. In more detail, snow storm is the hazard with the highest disaster risk for the A31 Highway. Similarly, earthquake is the hazard with the highest disaster risk for the water network in Barreiro. Three meteorological hazards ranked the highest for both the likelihood to occur and to cause disaster to the Øresund region. By contrast, the ranking of the hazards for the port of Oslo identified several scenarios with similar likelihood to cause disaster, which ranked very different in their likelihood to occur in the next 5 years. This raises question as to whether the most of least likely to occur scenarios is most suitable which can be answered in collaboration with the stakeholders. With regard to the operational hazards, the contamination of the water in the water source or the distribution network due to an acciden