Present‐Day Kinematics of Continental Greece and Balkans Revealed by Sentinel‐1 InSAR Data

Abstract

The Balkan Peninsula hosts the highest seismic activity in Europe, marked by numerous Mw6+ earthquakes in diverse tectonic settings. Assessing tectonic surface deformation is crucial to understand the forces controlling kinematics and, ultimately, constraining geodynamic models. However, because measuring slow velocity rates (a few mm/yr) with a sparse GNSS network is challenging, the Balkans surface deformation remain less studied than surrounding areas. We use Sentinel‐1 radar images (2014–2021) processed by the FLATSIM program, providing InSAR time series extending over 360 000 km2, at 240 m spatial resolution. By adapting a referencing method requiring minimal use of GNSS data, we produce a regional‐scale InSAR velocity field for western Balkans, referenced to ITRF14 and showing strong agreement with GNSS (<1 mm/yr). We decompose LOS velocities into horizontal and vertical components, constrain the location and amplitude of velocity gradients across active structures, and resolve both long‐ and short‐wavelength signals. Horizontal velocities are dominated by large‐scale tectonic motion, while vertical velocities are more heterogeneous, likely influenced by hydrology and anthropogenic processes. Kinematic analysis highlights key features: 4–5 mm/yr extension over 80 km in the inner Albanides and a major 250 km‐wide lithospheric shear zone in Greece, accommodating >2 cm/yr dextral motion, potentially linked to the North Anatolian Fault activity and Hellenic subduction rollback. Finally, we provide new constraints on compression going on in the Dinarides and Pannonian Basin. This study confirms the capability of InSAR to capture large‐wavelength plate motions in slowly deforming regions, providing a robust basis for future surface deformation and seismic hazard studies.