GIS-BASED LANDSLIDE VULNERABILITY MAPPING ALONG THE SUMATRAN FAULT: A CASE STUDY IN PASAMAN REGENCY, INDONESIA

Abstract

The study aims to provide an in-depth analysis of the influence of geological characteristics, land cover, slope levels, and rainfall intensity on landslide susceptibility. The study investigates the impact of the Sumatran Fault's active segments on geological instability and examines how human activities and climatic factors contribute to landslide risks. A quantitative approach integrates geological conditions, slope analysis, land cover classification, and rainfall data, validated through field testing. Data sources include geological maps, Shuttle Radar Topography Mission (SRTM) data, Landsat 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) 2024, and historical rainfall records. Supervised classification using the Maximum Likelihood algorithm and overlay analysis facilitated the identification of landslide-prone zones. The results reveal that igneous rocks dominate 41 % of the area, followed by sedimentary (33 %) and metamorphic rocks (25 %), with steep slopes (24–45%) covering 39 %. Annual rainfall exceeds 1500 mm, with areas receiving >2500 mm constituting 46 % of the region. These factors, combined with deforestation and unsustainable land practices, heighten landslide risks, particularly in the western fault zone. High-vulnerability areas account for 13 % of the region, concentrated in steep and fault-affected zones, while medium-vulnerability zones dominate at 86 %. The study concludes that Pasaman Regency requires integrated strategies, including slope stabilization, reforestation, and sustainable land-use practices, to mitigate landslide risks. Infrastructure resilience, community-based disaster management, and climate adaptation measures are critical for reducing socioeconomic impacts and enhancing environmental sustainability. The findings provide actionable insights for disaster risk reduction and land-use planning, emphasizing the interplay between natural and anthropogenic factors in landslide vulnerability.