Terrorism risks, chasing ghosts and infrastructure resilience

Abstract

Risk is the integration of threat, vulnerability and consequences, but threat is often based on worse-case thinking about the capability of terrorists to successfully plan and execute large-scale bombings. The paper looks at the nature of terrorists by exploring their capabilities and motivation, technical skills, and target selection. Key among this is the risk of progressive collapse of multi-storey buildings, and the track record of terrorists attacking targets in the West. In the past decade, most deaths from terrorists in the West have arisen from shooting attacks, vehicle impact, and mass transit bombings. In this case, there is little or no need to protect civilian buildings, bridges and other infrastructure from car or truck bombs unless there is a specific threat. Existing infrastructure has also proven to be highly resilient and robust against car and truck bombings. It is easy to overestimate the impacts of terrorist attacks. An improved understanding of the threat allows decision-makers to more effectively deploy resources to counter it, which includes appropriate design and assessment of civilian and military protective structures. A case study describes existing fatality risks from progressive collapse caused by a large vehicle bomb, and then assesses the costs and benefits of design (protective) measures mandated by the United States to mitigate against progressive collapse for new or leased federal government (civilian and defence) buildings.

Keywords:

• Risk
• terrorism
• infrastructure
• progressive collapse
• cost–benefit analysis
• risk reduction

Acknowledgements

The support of the Australian Research Council is gratefully acknowledged.