Time evolution of mining-related residual subsidence monitored over a 24-year period using InSAR in southern Alsace, France

From 1910 to 2002, the Mines Domaniales de Potasse d’Alsace (MDPA) exploited two potash layers, located at depths greater than 400 m in southern Upper Rhine Graben. This mining activity has caused surface subsidence, investigated here using SAR interferometry (InSAR) and Persistent Scatterer Interferometry (PSI) approach is used follow induced displacements over Alsatian potassic basin. The images acquired by three distinct satellites (ERS, ENVISAT, Sentinel-1) last 24 years cover both post-mining periods. Until 1996/1997, InSAR results do not fit high vertical displacement deduced from levelling campaigns due unwrapping errors are therefore reliable quantify subsidence. measurements become consistent, allowing us study subsidence following of mine. decreases quickly after end operations, with current estimated below 5 mm/yr 2018. obtained for period show a correlation between residual amplitude mined thickness. Taking together whole period, combined time series approximated sum exponential terms, which reveals role goaf compaction depth. shows that well suited monitoring small mining-induced phase, helping better mitigate related risk these regions.