Karangkemiri Village Landslide Potential Risk Mapping Based on Integrating Litho-structure and Morphology

Abstract

The Karangkemiri Village, Jeruklegi District, Cilacap Regency, Central Java Province, has a high risk of rock-mass movement. This is proven by the occurrence of a landslide in March 2020. The susceptibility of landslides is influenced by eight factors: slope, lithology, land cover, elevation, loading, rainfall, distance from rivers, and roads. Therefore, a landslide potential risk map is needed as a disaster mitigation effort. The integration between litho-structure and morphology was applied to understand the distribution of landslides vulnerability in Karangkemiri Village. The Analytical Hierarchy Process (AHP) method was adopted to find the dominant factor that causes a landslide. The result of this study was the geology of a research area consisting of 3 geomorphological units, namely the Structural Curve Slab Hills Unit (S3), Structural Waveed Hills Unit (S2), and Intrusion Unit to Basalt (S11). Stratigraphy of research areas is composed of sandstone (Tmph) and andesite lava (Tmpk) units. Special study methods use the AHP, assessment, and weighting against the landslide movement's causative factors, such calculations combined with primary and secondary data. The data and calculations were inserted into the parameter map then combined to obtain a map of the rock-mass movement susceptibility zone. Analyzing results show research areas divided into two levels of rock-mass movement vulnerability, medium, and high vulnerability levels. Medium levels of vulnerability cover 60% of Karangkemiri Village. Meanwhile, a high level of vulnerability encompasses 40% of Karangkemiri Village.