Understanding earthquake impact on communities through structural building damage and social vulnerability metrics

While methods exist to quantify the social vulnerabilities of communities to disasters as well as to estimate structural damage to residential buildings, little has been done to model the relationship between both types of vulnerabilities into a new, more comprehensive earthquake impact metric. This project explores methods for integrating damage estimates for an earthquake event along the Hayward Fault in California with social vulnerability indices with a building-level resolution. Structural damage to each building in the region is estimated probabilistically by the SimCenter's regional Workflow for Hazard and Loss Estimation (rWHALE) application framework. Social vulnerability is described using the Association of Bay Area Governments' (ABAG) Community Vulnerability Indicator (CVI) scores, calculated at the census block group level. CVI scores are disaggregated to match the building-level resolution of estimated structural damage. A metric is developed to combine the structural and social vulnerability data and to capture the effect of damage to neighboring buildings as an additional vulnerability indicator--a high proportion of buildings with significant damage within a certain radius can exacerbate vulnerability. The influence of certain parameters, like the selected neighborhood radius and the chosen building damage level, on the combined vulnerability metric is investigated using sensitivity analysis. The resulting combined vulnerability metric highlights different areas than those highlighted by damage data or CVI scores alone. This analysis demonstrates how a combined vulnerability metric can show a more nuanced impact of an earthquake on a community and how it can be used to inform interventions and mitigation policies on a regional scale.