PSI-based monitoring of structural deformations in Istanbul lagoon regions

Structural health monitoring (SHM) is a critical concern, especially for metropolitan cities exposed to natural hazards and environmental influences. Remote sensing plays a vital role in monitoring surface movements by taking advantage of regional image acquisition at regular intervals. In this study, the persistent scatterer interferometric synthetic aperture radar (PSInSAR) method was applied to Sentinel-1 satellite data acquired between 2018 and 2021 to monitor surface deformations in the lagoon region between the Büyükçekmece and Küçükçekmece Lakes, Istanbul. This region is particularly significant due to its proximity to the North Anatolian Fault Zone, the presence of active landslides, and clay-rich geological formations. Analysis of line-of-sight (LOS) deformation results from both ascending and descending orbits revealed deformation rates ranging from −9.5 to +7.3 mm/year and −9.9 to +6.6 mm/year, respectively. Six regions containing various engineering structures were selected for investigation. The study identified the impacts of active landslides on structures as well as the seasonal effects associated with clayey geological formations. Additionally, the deformations observed in coastal structures (e.g., piers and breakwaters) and thermal effects on bridge structures (e.g., viaducts) were evaluated based on the obtained results. Overall, the findings demonstrate that PSI effectively captures both regional and structure-specific deformation patterns. The study highlights the potential of PSI-based multi-temporal InSAR techniques for establishing continuous monitoring frameworks that support early warning, maintenance planning, and informed decision-making in urban renewal and infrastructure management in Istanbul.