LANDSLIDE SUSCEPTIBILITY MODEL OF CILILIN DISTRICT USING TRIGRS

Efforts to reduce the risk of a landslide require a good knowledge of the characteristics of rainfall on the susceptibility of a hilly area to landslides. The hilly area of Cililin Subdistrict in West Bandung Regency is one of the areas that often experience landslide disasters during heavy rainfalls. This paper presents the regional slope stability modeling using Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis (TRIGRS) to assess the effect of rainfall on the landslide susceptibility in Cililin Subdistrict. Results of modeling show that the locations of previous landslide incidents are generally located in the very high susceptibility zone. Besides, the areas of very high landslide susceptibility can increase twice due to the increase of rainfall intensity. The modeling also indicates that the landslide susceptibility of the area is mainly controlled by the topographical and geological factors. The high landslide susceptible zone is most likely to occur in the steep hilly areas made up of soils with low shear strength values which were originated from the Upper Miocene volcanic rocks. Whereas very gentle slope areas are made up of high shear strength soil originated from the Middle Miocene (pumice tuff and tuffaceous sandstone) that belongs to the low landslide susceptibility zone.