Developing and Verifying a Composite Indexof Disaster Potential Evaluationin Hillside Areas of Taipei

• Main Authors: Zhe-Ping Shen, 沈哲平
• Other Authors: 陳偉堯
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/k826c6

碩士 === 國立臺北科技大學 === 土木與防災研究所 === 96 === Located in the circum-Pacific seismic zone, Taiwan is characterized geomorphically by steep mountains and rapid waters and climatically by frequent typhoons and pouring rain, making landslides and debris flows the most common geologic hazards in Taiwan’s hillside regions that boast a total area of 2,630,000 hectares or 73% of the island’s entire area. The rapid increase in population in recent years has prompted people to develop hillside land. However, over-development of slope areas may bring about drastic impacts, damaging local ecological systems at the least and causing geologic disasters at its worst. In fact, the greater Taipei area (Taipei City and County) has witnessed as many as 867 slope hazards during the past 30 years, rendering prevention and management of hillside disasters a crucial priority. This study accordingly used 1 km x 1 km grids to analyze the disaster potential of hillside areas in the greater Taipei area. Based on related geographical data and historical records and consulting the evaluation criteria proposed in Disaster Prevention and Ecological Engineering Study of Hillside Regions surrounding Major Cities by Soil and Water Conservation Bureau, 12 factors were identified for developing a Composite Index of Disaster Potential Evaluation in the hillside districts of the greater Taipei area. The 12 factors are respectively land use, distribution of streams with potential for debris flow, rainfall, slope gradient, slope orientation, landslide, fault type, soil type, soil formation, population density, road density, consequent slope. Fortran application programs were adopted to simplify the complicated GIS data processing and to provide an integrated model for assisting various analysis tasks. Scores obtained by the proposed index were further verified by the collected historical data, and the geovisualization software of Google Earth was then used as the GIS platform to display the distribution of at-risk hillside districts in the greater Taipei area. Results of our study can be expected to provide related government agencies with useful references in decision making. Moreover, while factor scoring, data analysis, evaluation, display, and other tasks needed to be performed separately in previous methods, our proposed methode has the advantage of completing all the tasks with one single program. The model is further able to adjust the weight assigned to each factor to help reach more accurate evaluation.