| Summary: | 碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 91 === Regarding to the severe damage resulting from Chi-chi 921 Earthquake, it is urgent to construct a comprehensive strategy for evacuation, which is to arrange appropriate shelters and optimum evacuation routes in advance. The specific aims of this study are to explore how to conduct the residents to reach the designed shelters safely and efficiently as well, and to realize the virtual evacuation route through the network analysis of GIS.
In this research, the Nan-tou urban planning area is chosen as the study object. The earthquake resistance, which is estimated according to the shock resistant performance of roads, is applied as the safety index, and the travel-time cost, which is calculated in terms of the numbers of evacuative people, is used as the efficiency index. In order to integrate the safety and efficiency, the “Utility Theory” is adopted as the framework to evaluate the utilities and to judge the priority of factors. It transforms the two indices into the utility value and composes the relative importance between them. The final utility amount is the base of optimum route to the shelter assigned.
The survey indicated that safety is the top priority when people choose evacuation route, however, victims of the earthquake often choose the shortest but possibly more dangerous route to shelters under limited information. Matching the evacuative people’s personal route from starting point to the designed shelter with the optimum route, the shortest distance route, and the most travel-time-saving route, the degree of similarity were 79.4%, 86.4%, and 83.7% respectively. Based on the demand of Nan-tou urban planning area, this study suggested increasing three shelters which could improve the average distance of evacuation from 535m to 354.7m, and the average travel time from 416.9 sec. to 276.4 sec. It is obvious that the effect of evacuation had been improved substantially after newly building of shelters and new way to assigned shelters.
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