Brenda A¹, Masita², A Wibowo²

²Department of Geography, Faculty of Mathematics and Natural Sciences, University of Indonesia, 16424 Depok, Indonesia

endabrenda48@gmail.com

Landslide has been the most disaster happened in Cibodas as 4 cases of landslide disaster recorded in last 18 years from 2006 to 2022. It caused both physical and social aspect loses. High rainfall rate, steep slope, accused to be the triggers of landslide and as long as those things exist landslide will always be prone to happen in the future. Landslide is the movement of soil with a slope and moves it in an avalanche. This study aims to determine the causes and distribution of landslide susceptibility map using the frequency ratio. This study uses five causal factors, namely slop land use, lithology, and rainfall. According to the frequency ratio, the slope is the most influential than other factors. Hazard mapping can be done to mitigate the landslide by using qualitative method and quantitative method. The latter is refer to frequency ratio method used in this research. It is based on the relation between location that landslide occurred and the factor triggering it to happen. This method is implemented by using Geography Information System (GIS) and data such DEM Images, geological map 1:100.00, and topography map 1:25.000 and data rainfall rate. These data represents the factor that triggers landslide such as, slope, distance from drainage and fault, lithological maps, land use distribution, and precipitation. These factors will reconstructed becoming a 9x9m raster format and be overlaid resulting frequency ratio value. This frequency ratio value was calculated to get Landslide Hazard Index (LHI) which classified. The landslide susceptibility maps of 4 classes low, medium, high and very high landslide susceptibility classes in which represents landslide susceptibility map. The result of this method showed that researched area has low landslide susceptibility with 0,23% of total area, intermedia hazardous zone with 52,82% of total area and high classes zone with 45,63% of total area. And very high landslide susceptibility with 1,32% of total area.