Evolution of post-seismic ground deformation of the Athens 1999 earthquake observed by SAR interferometry

Co-seismic interferometric analysis was performed to investigate the spatial and temporal evolution of ground deformation related to the aftershock sequence of the Athens 1999 earthquake (M w =6.0). Differential interferograms (DInSAR) spanning different periods after the main seismic event showed variable ground deformation associated with the evolution of the post-seismic displacement field. Using ERS SAR images, four co-seismic differential interferograms were generated for the period from September to December of 1999, and spanning 16, 32, 67 and 102 days after the occurrence of the main shock. It was found that the cumulative ground deformation detected by DInSAR analysis was exponentially decreasing, following the declining rate of the post-seismic activity. The observed propagation of the ground deformation maxima towards the SE direction is consistent with the presence of clustered aftershock activity to the east of the epicentral area. The aforementioned evolution of deformation was also recognized by the observed expansion of the displacement field to the east.