Conceptualising multiple hazards and cascading effects on critical infrastructures

Despite increased research on ‘multiple hazards’ and ‘cascading effects’, ambiguity remains concerning terminology. This paper reviews the literature to explore how these two concepts are defined in relation to critical infrastructures and their vital societal functions. Next, it investigates how the concepts are operationalised in Swedish disaster risk management. Findings indicate that regardless of a wealth of methodologies assessing multiple hazards and their cascading effects, these are rarely used by local planners, suggesting a gap between scientific approaches and practical implementation. Research mainly captures multiple hazards and cascading effects through technical parameters related to the severity of a hazard or the direct physical impacts on infrastructure. Less focus has been placed on the wider or knock-on effects across sectors and how these translate into societal risk. Future research should move beyond traditional understandings of social vulnerabilities as only pre-existing, to analyse how cascading effects on infrastructure and services can put new social groups at risk.