Determination of Slow Surface Movements Around the 1915 Çanakkale Bridge During the 2022–2024 Period with Sentinel-1 Time Series

This study applied SBAS-InSAR to a dense Sentinel-1 Single Look Complex (SLC) archive (146 scenes) to monitor the 1915 Çanakkale Bridge between 2022 and 2024 (data up to 7 January 2025 were available and considered in the time-series reconstruction). The analysis produced LOS mean velocity maps and pointwise displacement time series, revealing localized displacement concentrated near the Lapseki approach. Extreme LOS values reached approximately −101 mm (min) and +77 mm (max) across the domain, while maximum cumulative LOS displacement near the Asian anchorage approached −90 mm. These satellite observations suggest that ground-related processes may contribute to the detected observed movement; however, LOS-only measurements and limited in situ validations preclude a definitive separation between structural and geotechnical drivers. We therefore recommend targeted GNSS/levelling campaigns, ascending (ASC)–descending (DSC) InSAR fusion, and formal uncertainty reporting to better constrain the deformation sources and magnitude. The study concluded that the SBAS-InSAR method is effective for long-term, contactless monitoring of bridges and similar mega structures. It was also determined that this method can be used to identify critical areas requiring ongoing monitoring.