ASSESSMENT OF GROUND SUBSIDENCE AND DEFORMATION IN LOKPAUKWU TOWN, UMUNNOCHI LOCAL GOVERNMENT AREA OF ABIA STATE, NIGERIA
Keywords:
Ground subsidence, Surface deformation, InSAR, GNSS, Remote sensing, Mining activities, Geospatial analysis, Lokpaukuwu town, NigeriaAbstract
Ground subsidence and surface deformation are major environmental and geotechnical challenges in mining regions due to continuous excavation and disturbance of subsurface geological formations. This study assessed the spatial and temporal characteristics of ground subsidence and deformation in Lokpaukwu town, Umunneochi Local Government Area of Abia State, Nigeria. The research employed satellite-based remote sensing and geospatial techniques to monitor surface displacement over a ten-year period (2014-2024). Multi-temporal Sentinel-1 Synthetic System (GNSS) measurements were used for ground validation. Additional datasets such as Shuttle Radar Topography Mission (SRTM) digital elevation models were integrated within a Geographic Information System (GIS) environment for spatial analysis and deformation mapping. Results revealed significant ground deformation across the study area, with vertical displacements values ranging from a maximum subsidence of -11.4mm to an uplift of +2.1mm during the observation period. The most intense subsidence events were recorded between 2016-2017 and 2021-2022, corresponding with periods of increased quarrying and mining activities. Trend analysis indicated an average subsidence rate of approximately -6.6mm/year, confirming persistent downward ground movement in active mining zones. Spatial velocity analysis further revealed areas of simultaneous vertical and horizontal displacement, indicating heightened geotechnical risk in certain parts of the town. The findings demonstrate the effectiveness of integrating InSAR, GNSS, and GIS techniques for monitoring mining-induced ground deformation. The study provides valuable information for land-use planning, environmental management, and the development of mitigation strategies to reduce subsidence-related hazards in mining environments.
References
1. Adeboye, A. B. (2011). Environmental impacts of quarrying activities in Nigeria. Journal of Environmental Management, 15(2), 45-53.
2. Bell, F. G., Stacey, T. R., & Genske, D. d. (2000). Mining substance and its environmental impacts. Environmental Geology, 40(1-2), 135-145.
3. Berardino, P., Fornaro, G., Lanari, R., & Sansosti, E. (2002). A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms. IEEE Transactions on Geoscience and Remote Sensing, 40(11), 2375-2383.
4. Ferretti, A., Prati, C., Rocca, F. (2001). Permanent scatterers in SAR interferometry. IEEE Transactions on Geoscience and Remote Sensing, 39(1), 8-20.
5. Galloway, D. L., & Burbey, T. J. (2011). Regional land subsidence accompanying groundwater extraction. Hydrogeology Journal, 19, 1459-1486.
6. Hofmann-Wellenhof, B., Lichtenegger, H., & Waste, E. (2008). GNSS – Global Navigation Satellite Systems: GPS, GLONASS, Galileo and more. Springer.
7. Johnson, R. B. (2005). Ground subsidence due to mining operations and its impact on infrastructure. Engineering Geology, 79(1), 45-58.
8. Kendall, M.G. (1975). Rank Correlation Methods. Charles Griffin.
9. Mann, H. B. (1945). Nonparametric tests against trend. Econometrica, 13(3), 245-259.
10. Massonnet, D., & Feigl, k. L. (1998). Radar interferometry and its application to changes in the Earth’s surface. Reviews of Geophysics, 36(4), 441-500.
11. Singh, M. M. (1992). Mine subsidence. SME Mining Engineering Handbook.
12. Zhou, W., Chen, Q., Zhang, Y., & Gong, H. (2020). Monitoring land subsidence in mining areas using inSAR techniques. Remote Sensing of Environment, 240, 111678.
