Detection of Crustal Deformation Using a Gravimetric and Multitemporal Interferometric SAR (MT-InSAR) Approach

Gradual crustal deformation processes and deposition may lead to new formations within affected geologies and geomorphologies. This study investigates crustal deformation within the well-known Anambra Sedimentary Basin of Nigeria by exploring interferometric synthetic aperture radar (InSAR) data from the Sentinel-1 satellite mission and tailored gravity model, a high-resolution gravity model integrating satellite, terrestrial and topographic data for the basin. Derived gravity maps demonstrate varying fault mechanisms and reveal the existence of NE–SW and NW–SE trending faults which may have led to the Oligocene formation along the NW–SE fault trend. The InSAR displacement maps reveal subsidence and uplift rates up to 8.8 mm/year, and 7.7 mm/year, respectively. This observed deformation in the Anambra Basin is due to fault-related factors as the highest subsidence rate is found in Ebonyi State between the Abakaliki anticlinorium and the Afikpo syncline and the differential loading in basin formation boundaries. Land subsidence is found to happen in the Anambra metropolis where urban sprawl is centred. Increased groundwater levels in the basin have also helped to reduce subsidence rates. This study has provided insights into the possible factors contributing to crustal deformation in the Anambra Basin, informing policymakers towards effective urban planning and resource management, and possible artificial groundwater recharge.