Identifikasi Kelongsoran di Kabupaten Toba Samosir Berdasarkan Faktor Alam dengan Sistem Informasi Geografis dan Citra Satelit

Abstract

Landslides are a phenomenon that occurs when soil or rocks on a slope move downward due to gravity, increased load, or reduced soil binding force. Landslides often occur in Indonesia due to natural factors such as high rainfall, slopes, fragile rocks, and earthquakes, as well as human factors. In this study, it is necessary to map the level of landslide vulnerability by utilizing the Geographic Information System (GIS). The main objective of the study was mapping the level of landslide vulnerability in Toba Regency by referring to the Minister of Public Works Regulation No. 22 of 2007. The research indicators are slope, soil type, rock type, rainfall, slope water system, seismicity, and vegetation. The research method used is scoring and weighting each indicator and overlay with the suitability of its geographical location. The results of the analysis of the landslide vulnerability level map obtained in Toba Regency contained 3 vulnerabilities, namely low vulnerability class (146,722 km2), medium vulnerability class (597,555 km2), and high vulnerability class (198,382 km2). The high vulnerability area is dominated by 2 subdistricts, namely Bonatua, Lunasi and Silaen. The area of vulnerability is dominated by 13 districts, namely Ajibata, Balige, Bor-bor, Habinsaran, Lumban Julu, Nassau, Parmaksian, Pintu Pohan Meranti, Porsea, Siantar Narumonda, Sigumpar, Tampahan and Uluan. The low vulnerability area is dominated by 1 sub-district, namely Laguboti.