Creating a Nationwide Composite Hazard Index Using Empirically Based Threat Assessment Approaches Applied to Open Geospatial Data

Sanam K. Aksha,Herbert E. Longenecker,Christopher T. Emrich,Yao Zhou

doi:10.3390/su14052685

Abstract

The US is exposed to myriad natural hazards causing USD billions in damages and thousands of fatalities each year. Significant population and economic growth during the last several decades have resulted in more people residing in hazardous places. However, consistent national-scale hazard threat assessment techniques reflecting the state of hazard knowledge are not readily available for application in risk and vulnerability assessments. Mapping natural hazard threats is the crucial first step in identifying and implementing threat reduction or mitigation strategies. In this study, we demonstrate applied GIS approaches for creating and synthesizing US hazard threat extents using publicly available data for 15 natural hazards. Individually mapping each threat enables empirically supported intervention development and the building of a Composite Hazard Index (CHI). Summarizing the hazard frequencies provides a novel representation of US hazardousness. Implementing cluster analysis to regionalize US counties based on their underlying hazard characteristics offers insight into hazard threats’ spatial (non-political) natures. The results indicate that the southeast, central plains, and coastal regions of the northeast had high hazard occurrence scores, whereas more moderate hazard scores were observed west of the continental divide. Furthermore, while no place is safe from hazard occurrence, identifying each region’s distinct “hazardousness” can support individualized risk assessments and mitigation intervention development.

Highlights

Natural hazards have caused severe damage and substantial loss and pose an increasing threat to the environment and society [1–3]
Severe thunderstorm (SVR) hazard threats based on storm-based warnings were distributed over the eastern two-thirds of the CONUS (Figure 1A)
The Composite Hazard Index is based on publicly available authoritative data analyzed and formatted into a novel hexagonal geospatial binning for better visualization and computational efficiency and reduced estimate bias

Summary

Introduction

Natural hazards have caused severe damage and substantial loss and pose an increasing threat to the environment and society [1–3]. Mitigating future hazard impacts requires an improved understanding of the spatial extent of hazard threats faced by communities, the expected severity of consequences for known hazards, and the intersection of threats and consequences with vulnerable populations and infrastructure. These three pieces of risk information will enable both planning and emergency management entities to formulate effective mitigation strategies and response plans for evacuation, sheltering, and relief distribution. Natural hazards are multidimensional across many space, time, hypsographic, geophysical, and socioeconomic factors, posing numerous cartographical challenges for mapping and communicating risk, often due to disregarding cartographic principles that overload or unbalance maps and making interpretation difficult [25–30]

Methods

Results

Discussion

Conclusion