Application of a Multi-Hazard Risk Assessment for Local Planning.

The utility of a multi-hazard risk-scape at the county level is significant for county, state, regional, and national policy makers who rely on broad and consistent assessments of hazard exposure and losses. In previous work, the Patterns of Risk using an Integrated Spatial Multi-Hazard (PRISM) approach creates an index of county risk for this purpose. While helpful across large areas, the approach lacks information needed at more localized scales. In this paper, we employ the PRISM approach to all 2015 census tracts in the US. Use of a land-cover approach, with spatial extents and modeled data from 11 natural and 4 technological hazard types, determines spatial exposures. Furthermore, census counts allow for the estimation of population exposures in each tract by hazard type. The results of the tract-level index reveal exposure patterns that contrast the original PRISM model, with a concentration of risk shifting eastward. The distribution of land-cover and population exposure more closely resemble the county index, revealing the importance of scale and land-cover considerations, along with the need for additional investigation of risk drivers. We provide an application of the risk and multi-hazard exposures in two major metropolitan areas to demonstrate utility of the approach at this scale.