「脆弱性(Vulnerability)」とは何か

Multi-variate and single-variable flood fragility and loss approaches for buildings

Social vulnerability indicators seek to identify populations susceptible to hazards based on aggregated sociodemographic data. Vulnerability indices are rarely validated with disaster outcome data at broad spatial scales, making it difficult to develop effective national scale strategies to mitigate loss for vulnerable populations. This paper validates social vulnerability indicators using two flood outcomes: death and damage. Regression models identify sociodemographic factors associated with variation in outcomes from 11,629 non-coastal flood events in the USA (2008–2012), controlling for flood intensity using stream gauge data. We compare models with (i) socioeconomic variables, (ii) the composite social vulnerability index (SoVI), and (iii) flood intensity variables only. The SoVI explains a larger portion of the variance in death (AIC = 2829) and damage (R2 = 0.125) than flood intensity alone (death—AIC = 2894; damage—R2 = 0.089), and models with individual sociodemographic factors perform best (death—AIC = 2696; damage—R2 = 0.229). Socioeconomic variables correlated with death (rural counties with a high proportion of elderly and young) differ from those related to property damage (rural counties with high percentage of Black, Hispanic and Native American populations below the poverty line). Results confirm that social vulnerability influences death and damage from floods in the USA. Model results indicate that social vulnerability models related to specific hazards and outcomes perform better than generic social vulnerability indices (e.g., SoVI) in predicting non-coastal flood death and damage. Hazard- and outcome-specific indices could be used to better direct efforts to ameliorate flood death and damage towards the people and places that need it most. Future validation studies should examine other flood outcomes, such as evacuation, migration and health, across scales.

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Using Disaster Outcomes to Validate Components of Social Vulnerability to Floods: Flood Deaths and Property Damage across the USA

Vulnerability of bridges to individual and multiple hazards- floods and earthquakes

Communities are changing the way they manage flood risk as a result of climate change which increases both the flood hazard intensity and frequency and therefore results in more flood exposure for the built environment. Quantifying the feasibility of policy changes requires a standardized approach that can allow a risk-informed decision. The current body of flood risk mitigation research is populated with a host of qualitative approaches to reduce flood risk at the building- and community-level. However, quantitative effects on physical infrastructure within the community at a detailed level, i.e. component- and building-level, are needed to provide decision-support for policymakers. In this study, a high-resolution quantitative approach is developed to determine the effect of policy change on flood losses at the community-level by integrating building information models with the community topology. This approach uses a portfolio of building archetypes to model flood vulnerability at the community-level. For each archetype within this portfolio, a systematic approach was developed to propagate uncertainties in the flood damage for each component within the building and thereby providing the total building damage in terms of exceedance probability of a set of prescribed damage states. The developed approach was used to investigate an array of community-level mitigation options that could control both the flood hazard and flood exposure. The analysis of an example community revealed that one mitigation policy is not enough to provide efficient flood protection and a suite of diverse mitigation techniques working in concert is more effective for major flood protection.

High-resolution flood risk approach to quantify the impact of policy change on flood losses at community-level

Floods can be devastating to communities and result in fatalities and injuries, negatively impacting the economy, and quality of life. This paper presents a review of community resilience research ...

Understanding flood risk in the context of community resilience modeling for the built environment: research needs and trends

Current flood vulnerability analyses rely on deterministic methods (e.g., stage–damage functions) to quantify resulting damage and losses to the built environment. While such approaches have been used extensively by communities, they do not enable the propagation of uncertainty into a risk- or resilience-informed decision process. In this paper, a method that allows the development of building fragility and building loss functions is articulated and applied to develop an archetype portfolio that can be used to model buildings in a typical community. The typical single-variable flood vulnerability function, normally based on flood depth, is extended to a multi-variate flood vulnerability function, which is a function of both flood depth and flood duration, thereby creating fragility surfaces. The portfolio presented herein consists of 15 building archetypes that can serve to populate a community-level model to predict damage and resulting functionality from a scenario flood event. The prediction of damage and functionality of buildings within a community is the first step in developing risk-informed mitigation decisions to improve community resilience.

Minimal Building Flood Fragility and Loss Function Portfolio for Resilience Analysis at the Community Level

Flood events are one of the most common natural disasters in the United States and can disrupt businesses; strain the financial resources of agencies that respond; and often leave household...

Omar M. Nofal

Papers

Understanding flood risk in the context of community resilience modeling for the built environment: research needs and trends

Multi-variate and single-variable flood fragility and loss approaches for buildings

High-resolution flood risk approach to quantify the impact of policy change on flood losses at community-level

Minimal Building Flood Fragility and Loss Function Portfolio for Resilience Analysis at the Community Level

Probabilistic Flood Loss Assessment at the Community Scale: Case Study of 2016 Flooding in Lumberton, North Carolina