Spatiotemporal quantification and trajectory modelling of land displacements in Western Greece using recent InSAR and GNSS observations

Detecting and monitoring ongoing surface deformation with satellite geodesy is fundamental for the analysis of geophysical processes and geohazards. Here, we focused on the area of Western Greece, due to its complex geophysical setting, characterized by numerous faults and high seismicity, and we quantified the spatiotemporal patterns of land displacements in the area from 2018 to 2022. We analysed Sentinel-1 Synthetic Aperture Radar (SAR) data with Multi-temporal Interferometric SAR (MT-InSAR) techniques and calibrated the derived estimates using velocity time series from multiple permanent Global Navigation Satellite System (GNSS) stations available in the area. The derived displacement time series were also compared with openly available data from the European Ground Motion Service (EGMS) and, jointly, were used to map possible active fault areas. In addition, trajectory modelling was performed in both MT-InSAR and GNSS velocity time series through the Greedy Automatic Signal Decomposition (GrAtSiD) algorithm, in order to identify seasonal loading and therefore improve detection of accelerations in tectonic or anthropogenic motion. Overall, the study explores recent geodetic observations with state-of-the-art data analysis techniques, and, building upon previous literature, offers a comprehensive spatiotemporal assessment of land displacements in Western Greece, with implications for scientific and engineering applications.