Analisis Daerah Rawan Longsor Menggunakan Sistem Informasi Geografis (SIG) Berdasarkan Aktivitas Manusia (Studi Kasus: Kabupaten Toba Samosir)

Abstract

Landslides are soil movements that are influenced by various physical properties of nature, including land use and infrastructure as well as geological structures, soils, drainage patterns, and slopes and land forms. Toba Samosir Regency, which is located in the northwest of North Sumatra Province, has an area of 202,180 km2 or about 3.19% of the province's area which reaches 7.160.000 hectares. Most of the highlands and hills of Toba Samosir Regency are located between 98°56' and 99°40' E and 2°03' and 2°40' N. Toba Samosir Regency has a tropical rainy climate because most of its area consists of mountains and hills with varying slopes, and is located at an altitude of 2.200 meters above sea level. Mapping of potential landslides in Toba Samosir Regency with a model of estimation of the reference of the Minister of Public Works Regulation No. 22 of 2007. One of the causes of landslides is human activities which include planting patterns, excavation and slope cutting, pond printing, drainage, construction development, population density, and mitigation efforts. Landslide vulnerability mapping using the Geographic Information System (GIS) was carried out by the method of weighting and overlapping (overlay) between the constituent parameters using QGIS software. Based on the results of the analysis, 3 (three) classes of vulnerability risk were obtained. For risks with a low vulnerability level of 92,87% or an area of 1651,.42 km2, medium is 7,01% or an area of 124.737 km2, and high is 0,12% or an area of 2,095 km2.