Analisis Kerawanan Longsor Berbasis Sistem Informasi Geografis Di Kecamatan Ngargoyoso Kabupaten Karanganyar

Ngargoyoso District is one of the districts in Karanganyar Regency which often experiences landslides. The Regional Disaster Management Agency (BPBD) of Karanganyar Regency recorded as many as 50 landslide events occurred in Ngargoyoso District in 2020. Factors causing landslides ranged from high rainfall to steep slopes. The purposes of this study 1) Analyze the level of landslide susceptibility in the research area, 2) Analyze the actual landslide distribution in the research area, 3) Formulate regional planning based on land use with the level of landslide susceptibility in the research area. The method used in this study is a survey with a unit analysis of land units, sampling using purposive sampling method. Methods of data analysis using tiered quantitative GIS which includes awarding grades/scoring and overlay analysis between land use and the level of vulnerability to landslides. The results of this study 1) Landslide hazard in Ngargoyoso District is divided into 2 classes, namely medium and high. Medium landslide susceptibility is 19 land units including V2-IV-L-SB, V2-VL-SB, V4-III-LK, V4-III-LP, V4-III-LS, V4-III-MK, V4-II- LK, V4-II-LP, V4-II-LS, V4-II-L-SB, V4-II-MS, V4-ILK, V4-ILP, V4-ILS, V4-STI, V4-IV-LK, V4-IV-LS, V4-IV-L-SB and V4-VL-SB. High landslide susceptibility consists of 11 land units including V2-IV-AH, V2-IV-AK, V2-VAH, V2-VLK, V4-IV-AP, V4-IV-LP, V4-IV-MK, V4-IV -MP, V4-IV-MS, V4-VLK and V6-IV-AK. 2) A total of 37 points of actual landslides are spread across the medium hazard class and the high hazard class, where most of them hit settlements. 3) Spatial planning in landslide-prone areas can be done by not building permanent buildings in landslide-prone areas, building retaining structures in landslide-prone locations, reforestation/replanting of plants with deep root systems and special spacing on steep slopes