Satellite Geodesy and Long-Period Ground Deformation Signals in Nigeria: Separating Anthropogenic, Climatic, and Tectonic Contributions

Ground deformation signals detected by satellite geodesy in Nigeria result from a superposition of tectonic loading, hydrological mass change, subsurface extraction, and anthropogenic mass loading, yet the methodological separation of these physically distinct contributions has not been rigorously attempted at the national scale, limiting both geophysical understanding and the translation of InSAR deformation data into infrastructure management intelligence. This dissertation applies advanced satellite geodesy methods to characterise and separate anthropogenic, climatic, and tectonic contributions to long-period ground deformation signals in Nigeria, making original contributions to applied geodesy, geodynamics, and infrastructure risk science. A seventeen-year Sentinel-1 and ALOS PALSAR-2 InSAR time-series is processed using the SqueeSAR algorithm to generate a national-scale ground deformation velocity field at 500-metre resolution. GRACE and GRACE-FO terrestrial water storage monthly gravity variations are downscaled and converted to loading deformation through Green's functions inversion, quantifying the climatic hydrological contribution to observed vertical motion. GPS time-series from forty CORS stations provide absolute vertical velocity constraints. A novel Deformation Source Separation Algorithm is developed using independent component analysis applied to the multi-sensor deformation time-series to isolate tectonic, hydrological loading, and anthropogenic deformation modes. Anthropogenic signatures associated with groundwater depletion in Lagos, Kano, and Abuja, hydrocarbon extraction in the Niger Delta, and reservoir impoundment at Kainji and Shiroro are individually characterised and their infrastructure risk implications assessed. Keywords: satellite geodesy, InSAR, ground deformation, Nigeria, source separation.