云南怒江流域泥石流敏感性空间分析

泥石流敏感性空间分析是通过评估诱发泥石流发生的因子,应用空间技术,进行泥石流发生的敏感性分析。本文探讨了GIS技术与敏感性分析的条件概率模型相结合的泥石流敏感性空间分析,并且阐述了GIS空间分析技术在泥石流敏感性制图中特有的优越性。研究区选择在遭受泥石流危害严重的云南怒江流域。用于泥石流敏感性分析评价的主要敏感因子包括地形坡度、岩土体类型、暴雨、河网密度、土地利用、地震动峰值加速度和人类活动。在对这些因子进行了敏感性空间分析的基础上,应用GIS的分析工具对敏感因子集成评价而产生了云南怒江流域泥石流敏感性评价图。泥石流敏感性评价图可以帮助规划者或工程师在土地发展规划中选择最佳建设场所,以减轻泥石流灾害的影响。

Susceptibility spatial analysis of debris flows in the Nujiang River Basin of Yunnan

Susceptibility spatial analysis of debris flows is to evaluate triggering factors for debris flow occurrence and divide the land surface into zones of varying degrees of susceptibility, based on spatial analysis technology. For the purposes of assessing debris flow susceptibility, a GIS spatial analysis combined with condition probability model of susceptibility analysis can estimate the probability of possible occurrence of debris flows. This paper discusses the potential of combining GIS technology with susceptibility modeling in debris flow analysis and also outlines the special advantage of GIS application for susceptibility mapping. The study area is located in the Nujiang River Basin of Yunnan, where is seriously suffering from debris flow hazards. Seven factors impacting debris flow susceptibility are analyzed: slope angle, rock and soil type, rainstorm distribution, trainage density, land use, seismic acceleration and human activities. According to the susceptibility spatial analysis of these factors,the susceptibility evaluation map was generated using GIS to conduct factor integration analysis. Then we classified each factor into three grades based on results of susceptibility calculation. With regard to debris flow susceptibility index, the study area is divided in to three susceptibility zones. The debris flow susceptibility zona-tion map shows that the high susceptibility zone covers an area of 4147 km2 or 12. 8% of the total study area; the middle susceptibility zone covers an area of 13931 km2 or 42. 9% and the low has an area of 13931 km2or 44. 3%. The susceptibility zonation map can help planners or engineers to choose the optimum construction locations for implemen-ting land development schemes in order to reduce the impact of debris flow on the study area.