LANDSLIDE SUSCEPTIBILITY MAPPING IN AGRICULTURAL LAND USING REMOTE SENSING AND GIS: A CASE STUDY IN EAST JAVA, INDONESIA

摘要

The purpose of this study is to assess landslide susceptibility in East Java, Indonesia using Remote Sensing and GIS. The study area covers Malang (3,775.8 Km2) and Blitar (1,726.8 Km2) districts. These areas face frequent problem of shallow landslides which are often caused by the intense rainfall in sloping agricultural area. Wrong land management practices which have been applied without any regard to soil conservation aggravate the occurrence of shallow landslides. Regional scale study is thus necessary to identify critical areas in order to meet sustainable agricultural farming practices. The deterministic Stability Index MAPping (SINMAP) model is used for this study. Input to the SINMAP model includes Digital Elevation Model (DEM) grid theme, landslide initiation point theme, soil-strength and hydrological parameters such as transmissivity and steady state recharge. Both the districts Malang and Blitar were divided into 7 and 5 calibration regions respectively, depending upon different geotechnical and hydrological characteristics. The model calibration was performed using all parameters and landslides as reference. The stability index map was produced by SINAMP model as the output which was further reclassified into 3 susceptibility classes and was compared with the existing landslide susceptibility map obtained by weighted overlay method. The model validation was performed using the previously identified landslide locations. The SINMAP model showed better results compared to weighted overlay method. The SINMAP model accuracy can be further improved by incorporating heterogeneous soil properties, spatial and temporal variation of rainfall and highly accurate DEM.