Monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements (LASUGEO)


his PhD research is defined under the framework of the BESLSPO BRAIN project: monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements (LASUGEO). Long-term land surface deformation patterns, and especially land subsidence in some Region of Interests (ROI) located in Belgium and in Germany were detected using Persistent Scatterers Interferometric Synthetic Aperture Radar (PS-InSAR) measurements and interpretation algorithms. Further, PS-InSAR will be applied on mid-resolution radar images such as ENVISAT ASAR and Sentinel-1A. Furthermore, using high spatial resolution of TerraSAR-X radar data along with their radar echo acquired at X-band will make possible to detect local subsidence with small extent and also sharply increase the density of the recognized persistent scatterers (PSs). The consolidation of the saturated geological layers during this period of time will be simulated in a 1-D geomechanical model. Effective stress variations in time will be deduced from the calculated pore pressure variations from a transient multi-layer groundwater flow model simulating the local hydrogeological conditions. Moreover, long-term time series of gravimetric data will be compared also to the time evolution of the deformations. All simulated results and observed measurements will be compared. In the last step, GPS/GNSS campaign measurements, at the position of artificial Corner Reflectors (CR) installed in various sites over each ROI will allow me to calibrate Sentinel-1A PS-InSAR results during at least three future years and will ensure that the detected land surface deformations are in a good agreement with measured observations.

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