GEOGRAPHICAL RESEARCH ›› 2005, Vol. 24 ›› Issue (2): 178-185.doi: 10.11821/yj2005020003

• Earth Surface Processes • Previous Articles     Next Articles

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

TANG Chuan   

  1. National Professional Laboratory for Geological Hazard Prevention and Geological Environment Protection, Chengdu University of Technology, Chengdu 610059, China
  • Received:2004-08-30 Revised:2004-12-17 Online:2005-04-15 Published:2005-04-15

Abstract:

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.

Key words: the Nujiang River Basin of Yunnan, debris flows, susceptibility, spatial analysis, GIS