Vulnerability assessment and landslide risk zoning through Geographic Information Systems

Abstract

Landslides and floods are recurrent hazards in the Nicaraguan Caribbean, where high rainfall, clay soils, and unplanned urban expansion increase territorial vulnerability. The purpose of this study was to assess vulnerability and to zone landslide and flood risk in sector 2 of the Loma Fresca neighborhood in the city of Bluefields. The research employs a mixed-methods, cross-sectional and descriptive-analytical approach. It was conducted through the integration of Geographic Information Stems (GIS), the Analytic Hierarchy Process (AHP), field observation, georeferenced surveying, and multitemporal analysis of Sentinel-2 imagery for the 2017–2023 period. For risk zoning, thematic layers of slope, precipitation, distance to drainage networks, land cover, infrastructure density, and structural vulnerability were developed, weighted through AHP pairwise comparison matrices, and integrated in ArcGIS Pro to generate hazard, vulnerability, and risk maps. The results showed that 63 % of the analyzed area presents high landslide risk and that approximately 48 % of the municipal territory registers some level of flood hazard. In addition, a loss of more than 31,000 ha of tree cover was identified, associated with urban and agricultural expansion, with direct effects on surface runoff and terrain instability. It is concluded that risk in Bluefields results from the interaction between natural and anthropogenic factors, which calls for strengthening land-use planning, environmental management, and urban planning through a preventive approach.