Stephanie E. Chang

A Framework to Quantitatively Assess and Enhance the Seismic Resilience of Communities

This paper presents a conceptual framework to define seismic resilience of communities and quantitative measures of resilience that can be useful for a coordinated research effort focusing on enhancing this resilience. This framework relies on the complementary measures of resilience: “Reduced failure probabilities,” “Reduced consequences from failures,” and “Reduced time to recovery.” The framework also includes quantitative measures of the “ends” of robustness and rapidity, and the “means” of resourcefulness and redundancy, and integrates those measures into the four dimensions of community resilience—technical, organizational, social, and economic—all of which can be used to quantify measures of resilience for various types of physical and organizational systems. Systems diagrams then establish the tasks required to achieve these objectives. This framework can be useful in future research to determine the resiliency of different units of analysis and systems, and to develop resiliency targets and detailed analytical procedures to generate these values.

Measuring Improvements in the Disaster Resilience of Communities

This paper demonstrates the concept of disaster resilience through the development and application of quantitative measures. As the idea of building disaster-resilient communities gains acceptance, new methods are needed that go beyond estimating monetary losses and that address the complex, multiple dimensions of resilience. These dimensions include technical, organizational, social, and economic facets. This paper first proposes resilience measures that relate expected losses in future disasters to a communitys seismic performance objectives. It then demonstrates these measures in a case study of the Memphis, Tennessee, water delivery system. An existing earthquake loss estimation model provides a starting point for quantifying resilience. The analysis compares two seismic retrofit strategies and finds that only one improves community resilience over the status quo. However, it does not raise resilience to an adequate degree. The exercise demonstrates that the resilience framework can be valuable for guiding mitigation and preparedness efforts. However, to fully implement the concept, new research on resilience is needed that goes beyond loss estimation modeling.

The Regional Economic Impact of an Earthquake: Direct and Indirect Effects of Electricity Lifeline Disruptions

This paper develops a methodology to estimate the regional economic impacts of electricity lifeline disruptions caused by a catastrophic earthquake. The methodology is based on specially designed input-output and linear programming models. A simulation of a major earthquake in the New Madrid Seismic Zone near Memphis, Tennessee, indicates the potential production loss over the recovery period could amount to as much as 7 percent of gross regional product. Reallocation of scarce electricity across sectors could reduce the impacts substantially. Additionally, an improved restoration pattern of electricity transmission substations across subareas could reduce losses even more.

MEASURING POST-DISASTER TRANSPORTATION SYSTEM PERFORMANCE: THE 1995 KOBE EARTHQUAKE IN COMPARATIVE PERSPECTIVE

Recent earthquake disasters have caused major damage to transportation networks, leading to significant economic disruption. While this suggests the need to evaluate total system performance in transportation risk assessment, in addition to examining the vulnerability of individual components such as bridges, no appropriate measures currently exist. This paper develops post-disaster system performance measures and applies them to the urban rail and highway transportation systems in the Kobe, Japan, region devastated by the 1995 Hyogoken-Nanbu earthquake. Performance is evaluated in terms of network coverage and transport accessibility. Performance degradation was much more severe for highways and railways than for other lifeline infrastructure systems. Both transportation systems fared poorly in the disaster but service restoration proceeded much more rapidly for rail. The restoration of highway system performance correlated closely with the recovery of highway traffic volumes. The paper further develops a measure of subarea transport accessibility and applies this to Kobes constituent city wards. Results indicate substantial spatial disparity that is maintained throughout the restoration period. Comparisons with the 1989 Loma Prieta and 1994 Northridge earthquakes in the US show that although these disasters caused notable damage to highway bridges, system performance degradation was small in comparison with the Kobe experience. The paper argues that explicitly measuring transportation system performance can greatly facilitate both understanding the effects of historic disasters and preparing for future hazard events.

Integrating Transportation Network and Regional Economic Models to Estimate the Costs of a Large Urban Earthquake

In this paper we summarize an integrated, operational model of losses due to earthquake impacts on transportation and industrial capacity, and how these losses affect the metropolitan economy. The procedure advances the information provided by transportation and activity system analysis techniques in ways that help capture the most important ecomonic implications of earthquakes. Network costs and origin-destination requirements are modeled endogenously and consistently. Indirect and induced losses associated with direct impacts on transportation and industrial capacity are distributed across zones and ecomonic sectors. Preliminary results are summarized for a magnitude 7.1 earthquake on the Elysian Park blind thrust fault in Los Angeles. Copyright 2001 BlackwellPublishers

Urban disaster recovery: a measurement framework and its application to the 1995 Kobe earthquake

This paper provides a framework for assessing empirical patterns of urban disaster recovery through the use of statistical indicators. Such a framework is needed to develop systematic knowledge on how cities recover from disasters. The proposed framework addresses such issues as defining recovery, filtering out exogenous influences unrelated to the disaster, and making comparisons across disparate areas or events. It is applied to document how Kobe City, Japan, recovered from the catastrophic 1995 earthquake. Findings indicate that while aggregate population regained pre-disaster levels in ten years, population had shifted away from the older urban core. Economic recovery was characterised by a three to four year temporary boost in reconstruction activities, followed by settlement at a level some ten per cent below pre-disaster levels. Other long-term effects included substantial losses of port activity and sectoral shifts toward services and large businesses. These patterns of change and disparity generally accelerated pre-disaster trends.

Probabilistic earthquake scenarios : Extending risk analysis methodologies to spatially distributed systems

This paper proposes a methodology by which probabilistic risk analysis methods can be extended to the assessment of urban lifeline systems. Probabilistic hazard information is commonly used for site-specific analysis. However, for such systems as highway networks, electric power grids, and regional health care delivery systems, the spatial correlation between earthquake ground motion across many sites is important in determining system functionality. The methodology developed in this paper first identifies a limited set of deterministic earthquake scenarios and evaluates infrastructure system-wide performance in each. It then assigns hazard-consistent probabilities to the scenarios in order to approximate the regional seismicity. The resulting probabilistic scenarios indicate the likelihood of exceeding various levels of system performance degradation. A demonstration for the Los Angeles study area highway network suggests that there is roughly a 50% probability of exceedance of Northridge-level disruption in 50 years. This methodology provides a means for selecting representative earthquake scenarios for response or mitigation planning.

Modeling spatial and economic impacts of disasters

1 Introduction.- I: Conceptual and Modeling Issues.- 2 Economic Principles, Issues, and Research Priorities in Hazard Loss Estimation.- 3 Indirect Losses from Natural Disasters: Measurement and Myth.- 4 Has September 11 Affected New York Citys Growth Potential?.- II: Economic Models.- 5 Measuring Economic Impacts of Disasters: Interregional Input-Output Analysis Using Sequential Interindustry Model.- 6 Geohazards in Social Systems: An Insurance Matrix Approach.- 7 Computable General Equilibrium Modeling of Electric Utility Lifeline Losses from Earthquakes.- 8 The Fall of the Iron Curtain and the Evolution of German Regional Labour Markets: A Self-Organized Criticality Perspective.- 9 Risk Perception, Location Choice and Land-use Patterns under Disaster Risk: Long-term Consequences of Information Provision in a Spatial Economy.- III: Integrative Models.- 10 The Dynamics of Recovery: A Framework.- 11 Earthquake Disaster Mitigation for Urban Transportation Systems: An Integrated Methodology That Builds on the Kobe and Northridge Experiences.- 12 Analysis of Economic Impacts of an Earthquake on Transportation Network.- 13 Benefit Cost Analysis for Renewal Planning of Existing Electric Power Equipment.- 14 Evaluating the Disaster Resilience of Power Networks and Grids.

Modeling Community Recovery from Earthquakes

This paper sets out the foundations for developing robust models of community recovery from earthquake disasters. Models that anticipate post-disaster trajectories are complementary to loss estimation models that predict damage and loss. Such models can serve as important decision support tools for increasing community resilience and reducing disaster vulnerability. The paper first presents a comprehensive conceptual model of recovery. The conceptual model enumerates important relationships between a communitys households, businesses, lifeline networks, and neighborhoods. The conceptual model can be operationalized to create a numerical model of recovery. To demonstrate this, we present a prototype computer simulation model and graphical user interface. As the model is intended for decision support, it is important to involve potential users in model development. We conducted a focus group involving Puget Sound, Washington, area disaster management practitioners to elicit local insight about community recovery and model development needs, using the prototype as stimulus. Important focus group issues included potential model inputs, useful recovery indicators, potential uses of recovery models, and suitable types of software systems.

Disasters and transport systems: loss, recovery and competition at the Port of Kobe after the 1995 earthquake

In the 1995 Great Hanshin earthquake, the Port of Kobe (Japan) suffered severe damage that essentially shut it down and required over two years to fully repair. This paper explores the impact of the disaster on the Port, focusing on international container traffic. Prior to the disaster, Kobe had ranked sixth among container ports worldwide; in 1997, it ranked 17th. Analysis reveals that foreign transhipment cargo was especially vulnerable to loss. This loss must be seen in the context of Asian port competition; indeed, the earthquake served to highlight and accelerate pre-disaster economic trends. Implications for seismically vulnerable ports in the US and Canada are discussed.