Multi-Hazard Risk Assessment

Multi-hazard risk assessment estimates and compares the risk that several distinct hazards pose to a shared set of people and assets, rather than studying each peril in isolation. Building on the risk-science convention that risk is the product of hazard, exposure and vulnerability, the approach characterizes each hazard's intensity-frequency behavior, overlays a common exposure inventory, applies hazard-specific vulnerability functions, and then aggregates the resulting losses across hazards. Kappes, Keiler, von Elverfeldt and Glade's 2012 review in Natural Hazards set out the central difficulties: hazards differ in their spatial footprint, return period, and measurement units, and they can interact through cascades and coincidences, so a defensible multi-hazard assessment must harmonize incompatible inputs and explicitly model how perils relate. ISO/IEC 31010 places the method within the standard toolbox of risk-assessment techniques used to support prioritization and treatment decisions.