Ground Displacement Associated with the September 2024 Mpape Tremor, Abuja, Nigeria: A Sentinel-1 DInSAR Analysis

Abstract

On 17 September 2024, a moderate tremor of magnitude Mw 3.0 was reported in the Mpape area of Abuja, Nigeria, raising concern about ground stability in a rapidly expanding urban environment. This study applied Sentinel-1 C-band Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine line-of-sight (LOS) ground displacement associated with the event. Two Sentinel-1A single-look complex images acquired before and after the tremor, on 29 August and 10 October 2024, were processed through a standard workflow involving orbit correction, coregistration, interferogram generation, topographic phase removal, Goldstein filtering, phase unwrapping and terrain correction. The results showed high interferometric coherence in built-up areas, with values exceeding 0.96, whereas vegetated and steep-slope areas had lower coherence and were excluded from reliable displacement interpretation. The maximum LOS displacement near the reported epicentral zone was estimated at 0.89 ± 0.3 cm, while the mean deformation of reliable pixels remained minor. The deformation pattern was localized and limited in spatial extent, with no evidence of coherent surface rupture or widespread hazardous subsidence. The pattern is consistent with a small, shallow seismic source; however, the use of only two SAR acquisitions limits the separation of coseismic, post-seismic, atmospheric, seasonal and anthropogenic effects. Continued InSAR monitoring supported by ground-based seismic and geodetic observations is recommended for Abuja and nearby basement-complex terrains.