SUBSIDENCE MONITORING IN THE COASTAL REGION OF NIGERIA USING MULTI TEMPORAL INTERFEROMETRIC SYNTHETIC APERTURE RADAR (MT -INSAR)

摘要

The uncontrolled exploitation of the groundwater, oil and gas in the Nigerian coastal geosyncline has led to progressive decline of the aquifer level and a continuous need for opening deeper drillings to exploit deeper aquifers. From the analysis of the interferometric results derived from the application of Multi-Temporal Interferometry (MT-InSAR) technique, Lagos state appears to be subsiding conically up to -7 mm/yr. The velocity rates of subsidence in the surrounding cities like Lekki, Badagry, Ikorodu and Epe are much higher than in Lagos city. These preliminary investigation results reveal heavy structures, in particular buildings, that were seen constructed mostly on the sand filled areas where the sediments compaction rates is very high.