Doctoral Dissertation Research: Measuring the Environmental Context of Social Vulnerability to Urban Earthquake Hazards: An Integrative Remote Sensing and GIS Approach

虽然许多灾难性事件，如地震、洪水、飓风和龙卷风，可能被定性为自然灾害，但与这些事件相关的破坏程度，往往是自然力量本身和发生地点的人和人文环境的产物。如果考虑到与自然灾害相关的风险，这一点尤其正确。本博士论文研究项目将发展基于遥感、地理信息系统（GIS）和空间分析技术的城市地震风险生态综合分析方法。该研究以人类生态视角的概念框架为指导，并建议使用建筑和自然环境作为语境过滤器来理解与城市地震灾害相关的社会过程。这项研究的主要目的是探索遥感和地理信息系统技术在确定城市土地覆盖属性方面的效用，这些属性与社会易受地震危害的高低程度密切相关。本研究将检验社会脆弱性反映在不同人口群体所占据的城市邻里空间结构特征上的假设，如地理条件、聚落的形态与发展、开放空间的结构等。其中许多特征是由某些城市土地覆盖属性（如建筑材料和土壤类型）在物理上表现出来的，从而提供了一种通过使用遥感和地理信息系统来衡量这些特征的相对重要性的手段。这项研究的基本假设将在洛杉矶大都市区进行检验，这是一个充满活力、数据丰富的城市区域，1994年受到一次大地震灾害的影响。研究计划包括三个相互关联的任务。首先，将开发一个GIS原型，使用一套措施来评估美国城市当代城市领域的脆弱性，而不包括遥感变量。其次，将使用地震事件前收集的数据来演示遥感图像的效用。这些数据将提供与研究地点社会脆弱性变化相关的土地覆盖属性的空间明确变量。第三项任务将包括通过完全基于这些变量重新评估研究地点的脆弱性来检验遥感变量的有效性。第一和第三项任务的结果将与1994年地震灾害所报告的损失数字进行比较和核实。这个项目的动机来自于开发一种灵活的脆弱性分析方法的经验基础的愿望，这种方法可以平衡两种相互竞争的需求。首先需要的是增进对产生易受害形态的各种环境因素和社会因素之间的联系的了解。第二，需要为开展地方缓解工作的规划者和决策者提供一种切实可行的方法，以生成脆弱社区的具体概况，并监测这些概况的变化。因此，该项目更广泛的贡献是理论和实证的。从理论角度来看，该研究将通过回答有关地震风险的生态学以及不同的社会脆弱性如何与城市地区物理环境的变化联系起来的问题，为危害研究做出贡献。从经验的角度来看，该项目的产品将有助于减轻灾害，为决策者提供探索脆弱性模式的工具，从而有助于以满足可持续减轻灾害需要的方式执行政策。所采用的方法为如何将评估脆弱性的技术转化为地方政府易于使用的程序提供了一个模型，这可以提高地方应用措施的有效性，从而防止地震灾害成为重大的人类灾害。所讨论的技术成本相对较低，因此可以对这种方法进行适当修改，以挽救其他发达国家和发展中国家的生命。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

Although many catastrophic events like earthquakes, floods, hurricanes, and tornadoes may be characterized as natural disasters, the amount of devastation associated with such events often is as much a product of the people and human landscapes where they occur as the natural forces themselves. This is especially true if one tries to consider the risks associated with natural hazards. This doctoral dissertation research project will develop an integrative methodology for the analysis of the ecology of urban earthquake risks based on the techniques of remote sensing, geographic information systems (GIS) and spatial analysis. The research is guided by a conceptual framework that takes a human ecological perspective and suggests the use of the built and natural environments as contextual filters to understand social processes associated with urban earthquake disasters. The major thrust of the research is oriented toward the exploration of the utility of remote sensing and GIS techniques in identifying urban land-cover attributes that are strongly associated with high and low levels of social vulnerability to earthquake hazards. The research will test the hypothesis that social vulnerability is reflected in the characteristics of the spatial structure of the urban neighborhoods that various population groups occupy, such as geographic conditions, the form and development of settlements, and structure of open spaces. Many of these characteristics are physically represented by certain urban land-cover attributes, such as constructions materials and soil types, thus providing a means of measuring the relative importance of such characteristics through the use of remote sensing and GIS. The basic hypothesis of this research will be tested in the Los Angeles metropolitan area, a dynamic, data-rich urban region which was affected in 1994 by a major earthquake disaster. The research plan consists of three interrelated tasks. First, a GIS prototype will be developed using a set of measures for assessing vulnerability in the contemporary urban realm of American cities without the inclusion of remotely sensed variables. Second, the utility of remote sensing imagery will be demonstrated using data collected before the earthquake event. These data will provide spatially explicit variables regarding land-cover attributes associated with variations of social vulnerability in the study sites. The third task will consist of a test of the validity of the remotely sensed variables by re-assessing vulnerability in the study sites based exclusively on such variables. The results of the first and third tasks will be compared and validated against reported damage figures from the 1994 earthquake disaster.The motivation for this project comes from the desire to develop an empirical base for a flexible approach to vulnerability analysis that can balance two competing demands. The first need is to improve the understanding of the linkage among various contextual and social factors that produce vulnerability patterns. The second is the need for offering a practical way for planners and decision makers undertaking local mitigation efforts to generate concrete profiles of vulnerable communities and to monitor changes in these profiles. The broader contributions of this project therefore are both theoretical and empirical. From a theoretical perspective, the research will contribute to hazard research by answering questions regarding the ecology of earthquake risk and how differential social vulnerability is connected to variations in the physical settings of urban areas. From an empirical viewpoint, the product of this project will contribute to hazard mitigation efforts by providing decision makers with tools for exploring patterns of vulnerability and hence for implementing policies in a manner that fulfills the needs of sustainable hazard mitigation. The methods employed offer a model of how to translate the technology for assessing vulnerability into procedures for easy use by local governments, which can increase the effectiveness of locally applied measures that could prevent earthquake hazards from becoming major human disasters. The techniques in question are relatively low-cost and therefore the approach could suitably be modified to save lives in other developed and developing countries. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.