2008 年 16 巻 p. 15-25
This paper describes the quantitative analysis of landslide on mountainous region of Kanagawa Prefecture, Japan using the records of pervious landslide data along the road network. It determines the landslide susceptibility of an area using the Certainty Factor Model (CF) and uses SINMAP model to indicate Stability Index (SI) and susceptibility classes in GIS application. The affecting parameters such, as lithology, slope angle, slope aspect, elevation, land use and rainfall are derived and spatial database was established. The CF value that was used as GIS attributes to integrate the parameters by summation indicated it is certain that landslide will occur along sandstone and shale area with CF value of 0.38.The slope of 20°-30° had high certainty and slope facing northwest and west showed high certainty for landslide as area unexposed to sun have lower temperature and higher soil moisture which are favorable for landslide occurrence. The land use indicated higher certainity of landslides in barren land with grasses and the rain parameter indicated that certainity increases with an increase of rainfall intensity. The integration of the geomorphological parameters in SINMAP model along with the landslide data indicated the relation between contribution area and the slope. The failure slope range indicated by SINMAP model agreed with that of the CF model. The generated susceptibility class map showed similar trend while comparing with the actual landslide data of the area and also indicated the susceptibile area similar to that with CF model.
