8. Cascading Disasters: Multiple Risk Reduction and Resilience

The connectedness and interdependency of modern society mean that, when disaster strikes, it is likely to involve cascading consequences. This chapter examines the nature of cascading disasters in terms of the cross-sectoral linkages that they exploit. Escalation points can arise, in which interactions between different forms and scales of vulnerability lead to impacts that may be greater or more serious than those of the hazard that started the cascade. Natural and technological events combine in cascading disasters to produce complex consequences. To understand such processes, a full understanding of disaster vulnerability is required. A model is presented which avoids the usual categories into which forms of vulnerability are placed and encourages instead a more holistic, cross-disciplinary approach to the phenomenon. The chapter then examines how cause is turned into effect by the interaction of specific and general vulnerability, representing direct causes of disaster and contributory or contextual factors, respectively. Dealing with cascading disasters requires planning based upon suites of scenarios that represent different sets of cascade paths. Foresight and mitigation need plans to be based on understanding the range of possible cascade mechanisms and providing redundancy in the proposed solutions to them.