HAZARD, VULNERABILITY, AND RISK ANALYSIS
This paper describes how preimpact conditions act together with event-specific conditions to produce a disaster’s physical and social impacts. These disaster impacts can be reduced by emergency management interventions. In addition, this chapter discusses how emergency managers can assess the preimpact conditions that produce disaster vulnerability within their communities. The chapter concludes with a discussion of vulnerability dynamics and methods for disseminating hazard/vulnerability data.
Introduction
A disaster occurs when an extreme event exceeds a community’s ability to cope with that event. Understanding the process by which natural disasters produce community impacts is important for four reasons. First, information from this process is needed to identify the preimpact conditions that make communities vulnerable to disaster impacts. Second, information about the disaster impact process can be used to identify specific segments of each community that will be affected disproportionately (e.g., low income households, ethnic minorities, or specific types of businesses). Third, information about the disaster impact process can be used to identify the event-specific conditions that determine the level of disaster impact. Fourth, an understanding of disaster impact process allows planners to identify suitable emergency management interventions. The process by which disasters produce community impacts can be explained in terms of models proposed by Cutter (1996) and Lindell and Prater (2003). Specifically, Figure 6-1 indicates the effects of a disaster are determined by three preimpact conditions—hazard exposure, physical vulnerability, and social vulnerability. There also are three event-specific conditions, hazard event characteristics, improvised disaster responses, and improvised disaster recovery. Two of the