The capacity of a system, community or society potentially exposed to hazards to adapt, by resisting or changing in order to reach and maintain an acceptable level of functioning and structure. This is determined by the degree to which the social system is capable of organizing itself to increase this capacity for learning from past disasters for better future protection and to improve risk reduction measures (UN ISDR, 2006; also SDR, 2005).
The ability of social units (e.g., organizations, communities) to mitigate risk and contain the effects of disasters, and carry out recovery activities in ways that minimize social disruption while also minimizing the effects of future disasters. Disaster Resilience may be characterized by reduced likelihood of damage to and failure of critical infrastructure, systems, and components; reduced injuries, lives lost, damage, and negative economic and social impacts; and reduced time required to restore a specific system or set of systems to normal or pre-disaster levels of functionality (MCEER, 2008).
Of these, the Department of Homeland Security’s National Infrastructure Protection Program (NIPP) definition is narrower in scope than the MCEER (Multidisciplinary Center for Earthquake Engineering Research) definition, and the concept of maintaining function is somewhat vague in the former. It could include maintaining as high a function as possible at the moment the disaster strikes. Alternatively, resilience might refer only to maintaining function through activities undertaken after the event, and hence would not necessarily include pre-event mitigation. This focus on post-shock activities (both inherent and adaptive) and the emphasis on recovery as both goal and process are more consistent with the origins of the term resilience. The United Nations International Strategy for Disaster Reduction (ISDR) definition, in contrast, departs further from the origins of the term and appears to emphasize pre-disaster mitigation and preparedness, with the only allusion to the idea of rebounding from a disaster relating to the speed of recovery. It does, however, emphasize that resilience is a process. This definition is also used in the National Science and Technology Council’s Grand Challenges for Disaster Reduction.
Although the 2008 NEHRP Strategic Plan (NIST, 2008; p.47) adopts this latter definition, for purposes of the roadmap, it is important to consider several issues:
• “National earthquake resilience” should primarily involve building resilience at the level of communities. It is also important, however, to prepare for the rare instances where earthquake disasters could extend beyond localities and have national-level consequences (see Box 2.1).
• In order for communities to be more resilient, support from both state and federal levels is required.