Rapid Subsidence Mapping in Awka Metropolis Using Synthethic Aperture Radar

This study investigates the spatial and temporal dynamics of land subsidence in Awka Metropolis between 2019 and 2024 using Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR). The objectives include identifying zones of subsidence, estimating the annual rate of vertical ground displacement, and classifying subsidence severity. Sentinel-1A SAR data were acquired and processed using the SNAP software and Stanford Method for Persistent Scatterers (StaMPS) in MATLAB. The results revealed severe subsidence in key urban areas such as Ifite (4.1 cm/year), Unizik Temporary Site (3.7 cm/year), and Agu Awka (3.5 cm/year), attributed largely to urban expansion, groundwater withdrawal, and construction load. The classification categorized the subsidence zones into low, moderate, and high risk, thus providing critical spatial insights for mitigation and planning. The study recommends the integration of InSAR-based early warning systems and sustainable land-use practices to prevent future infrastructural and environmental damage.