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

San Diego State University Foundation, San Diego CA

Investigators

Abstract

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.