Mapping of Hazard Areas and Risk Analysis of Landslide Disaster with Geographic Information Systems (GIS) (Case Study in Ciremai Foothills Region, Majalengka District).

Abstract

Landslide disaster is one of the natural disasters that often occur in Indonesia and is generally common in mountainous regions, the rainy season and is closely related to natural conditions such as soil type, rock type, rainfall, land slope and land cover. The aim of this study is to mapping hazard landslide areas and to analyze the risk of landslides in the Ciremai foothills region Majalengka district. Puslittanak (2004) is using to be a model of analyzing landslide susceptibility prediction in study area, the formula is Total Score = 0,3 FRain Falls +0,2 FGeology +0,2 FLand Slope +0,2 FLand Cover +0,1 FSoil Types. Risk analysis was analyzed by quantitative models based on research of Alhasanah (2006) through the overlaying property map score (infrastructure map, road map and land cover) with landslide vulnerability map. In study area, low landslide susceptibility class dominated by flat topography, the dominant rock type is Qa (Aluvium), soil type is Latosol and rainfall intensity 2500-3000 mm/year. Medium landslide susceptibility occur in flat to a relatively steep slope with the type soil dominated by Andosol and level of rainfall intensity is 2500-3000 mm/year. At high landslide susceptibility, dominated land cover is forest with steep topography (15-30%), rock type is dominated by Qvu and the soil type is Andosol with rainfall 3000-3500 mm / year. Very high vulnerability to landslides mostly located in forest areas with very steep slope (>45%), high rainfall intensity 3000-3500 mm/year and dominated by Qyu rock type and Andosol soil type. Based on the analysis of vulnerability map, in area study obtained low vulnerability covered area 2160,45 hectares, medium vulnerability with covered 15319,71 hectares, 21992,49 hectares of high landslide vulnerability and very high vulnerability covered 6191, 91 hectares. Very high vulnerability mostly located in Argapura with 2811,78 hectares (45,41%). Based on the analysis of risk maps, the area of research has a low risk area with a wide level of 13212,36 hectares (28,93%), medium risk level covered 31507,38 hectares (69,00%), high risk level covered 806,94 hectares ( 1,77%) and very high risk level covered 137,88 hectares (0,30%). Areal distribution of very high risk level areas are the largest in the Maja with covered area 32,67 hectares (23,69%).