Radar Space Measurements of the Deforming Trends at Northern Greece Resulting from Underground Water Activity

Abstract

Two case studies, in northern Greece, that monitor surface deformation were presented. Both are related to aquifer overexploitation and its impact on the earth’s surface. Using the archive of ERS and ENVISAT satellites, radar time series were performed applying the PS and SBAS techniques. For the justification of the remote sensing results and the interpretation of the physical mechanism behind the detected deformation, in situ data were also exploited. The areas of focus are: the village of Kalochori, a significant industrial hub, and the Anthemountas basin, an active tectonic region, both located in the vicinity of the metropolitan area of Thessaloniki. The Kalochori case indicated that the aquifer activity is directly affecting the surface movements. A low underground water level in the 90’s caused a subsidence of more than 20 mm/year and the subsequent recharge of the aquifers in the 2000s caused a surface rebound with a rate of up to +12 mm/year. Regarding Anthemountas basin, the subsidence has a maximum rate of −18 mm/year in the 90’s, and the deformation appears to exist over the whole basin. In conclusion both cases reveal that northern Greece is suffering from a hazard imposed by anthropogenic causes.