RISK ANALYSIS OF LANDSLIDE IMPACTS ON SETTLEMENTS IN KARANGANYAR, CENTRAL JAVA, INDONESIA

Indonesia is prone to landslides resulting from high variability in topographic conditions and rainfall characteristics. These events are likely to increase in frequency because of the spread of land degradation in the region. At least 50 landslide occurs every year between 2003-2005 in West Sumatra, North Sumatra, South Sulawesi, Papua, and Java Island including the research area, Karanganyar district, Central Java. This study aims to analyze the risk of landslides on settlements in Karanganyar district, Central Java, Indonesia. The integrated method between the statistical methods, field observation, and spatial analysis using Geographic Information Systems (GIS). The bivariate statistical approach was applied to determine the weight of each variable, based on existing landslide events. A black box model based on the landslide density analysis was prepared by connecting the primary data for landslide events and the parameters applied (topography, geology, soil, land use and the rainfall intensity). The level of risk was then analyzed by applying the function risk = hazard x vulnerability to the GIS platform. The results show that landslide tend to occurs in the area with physical characteristics as follow: slope between 8-150; consists of Wonosari Formation (sediment reeflimestone); reddish brown latosol; utilized as dry land farming; and has high rainfall intensity (4,000-5,000 mm/ year). These model can be used to generate landslide-damage and risk-distribution maps of settlements which could be used for mitigation purposes.