3D Modeling Using Unmanned Aerial Vehicles (UAV) in Landslide Risk Assessment and Mitigation Based on Indigenous Knowledge (Case Study: Tawangmangu Sub-district, Karanganyar Regency, Indonesia)

The advancement of Geographic Information System (GIS) technology through 3D modeling has significantly improved disaster risk analysis, particularly for landslides. This study utilized Unmanned Aerial Vehicles (UAVs) and Agisoft Metashape software to produce accurate 3D models, which were used to identify the location, volume, displacement, and distribution of landslide impacts in Tawangmangu Sub-district, Karanganyar Regency. This area is characterized by hilly topography with slopes > 45% and frequent land-use changes that exacerbate landslide risks. The 3D modeling process involved several key steps: aerial image acquisition using UAVs at an altitude of 126 meters, photo processing with Agisoft Metashape to generate orthomosaic maps, Digital Elevation Models (DEM), and geospatial analysis. Camera calibration was performed to enhance accuracy, while risk analyze using overlay and scoring methods were applied to hazard, vulnerability, and community capacity parameters in accordance with National Disaster Management Agency (BNPB) Regulation No. 02 of 2012. The results revealed that most of Tawangmangu Sub-district falls into the medium-risk category for landslides, covering an area of 4023.45 hectares, with the highest risk levels identified in Sepanjang and Tawangmangu villages. The 3D models indicated translational landslides, with soil displacement volumes ranging from −5409.3 m^3 to −991, 808 m^3, causing infrastructure damage and road closures. Mitigation efforts integrated UAV technology for realtime monitoring and indigenous knowledge in the form of coping strategies passed down through generations. UAV data was also utilized for disaster simulation, community training, and evidence-based mitigation planning, such as designing retaining walls and evacuation routes. This study highlights the importance of combining UAV technology and indigenous knowledge to enhance community capacity for sustainable and independent disaster risk reduction in landslide-prone areas.