Need for a Probabilistic-Based Multiple Natural Hazards Assessment
Within the United States, the vulnerability to hazards is rising significantly because more dwellings and infrastructure are being built along the human-environmental interface (Federal Emergency Management Agency, 1998). This leaves little buffer between communities and hazardous natural processes. Within this context, critical information on the magnitude, frequency, and distribution of the hazardous processes is needed for developing appropriate mitigation strategies. The US Disaster Mitigation Act of 2000 (i.e., DMA 2000) formally established a hazard mitigation program that requires state, tribal, and local governments to perform mitigation planning as part of their applications for aid to mitigate hazards. This includes the development of multi-hazard maps used in composite hazard, vulnerability, and risk assessments of communities. As recognized in DMA 2000 and recent research publications, studies done on individual natural hazards are limited because they do not consider a composite measure for the multiple hazardous processes that impact the landscape (Tate et al., 2010; Greiving et al., 2006; Bell & Glade, 2004; Cutter et al., 2000). Probabilistic-based multiple natural hazards assessments (MNHAs) can provide a more realistic perspective on the occurrence and significance of natural hazards across the landscape. MNHAs can be used as inputs for completing vulnerability and risk assessments, which ultimately provide a better understanding of the problems facing communities along the human-environmental interface.
With today’s easy access to advanced geospatial technologies and digital data through various organizations’ web portals, community planners can conduct detailed probabilistic hazards analyses and incorporate the results into their master plans to prioritize pre-disaster mitigation efforts in their communities. However, most do not have the time, resources (human or software) or expertise to develop multi-hazard assessments that can be analyzed as well as input into multi-hazard vulnerability and risk assessments. Such was the impetus that led to the development of this model, constructed using Geographic Information System (GIS) object-based graphic tools that are easily executed in a common GIS platform on a local computer or through web-based services.
Community planners, geospatial analysts, emergency managers, and decision makers (i.e., the stakeholders) are intended as the primary audience for this model. The community-scale information generated from such an assessment will lead to a good understanding of the geographic distributions, the critical thresholds (magnitude), and the exceedance probabilities of the predominant hazards in the community. This will lead to better understanding of the vulnerabilities and risks that require decisions on how to effectively distribute resources to mitigate the hazards, provide advance warning, and lead to improved response times in disaster situations.