Velocity dynamics in Türkiye’s nationwide cadastral network

Turkey, situated within a tectonically active region, is subject to frequent seismic events that induce crustal deformation of varying magnitudes. These deformations differentially affect geodetic infrastructure across distinct zones, leading to measurable variations in the velocity fields of geodetic benchmarks. This study investigates continuous velocity changes observed at geodetic sites across Turkey, resulting from cumulative deformation between the establishment of the geodetic network and the present day. Velocity components (Vx, Vy, Vz) for C1 and C2 benchmarks were obtained from the Map Data Bank (HBB) and compared with contemporary velocities predicted using the Turkish National Reference Frame (TUREF) published by the General Directorate of Mapping (HGM). Cartesian velocities of 482 C1 and C2 sites distributed across Turkey were analyzed, and component-based velocity difference maps were generated. Maximum velocity discrepancies were determined as 25 mm/year (X-component), 39 mm/year (Y-component), and 37 mm/year (Z-component). These inconsistencies highlight the potential for decimeter-level errors in the coordinates during long-term epoch transformations, which may propagate into cadastral infrastructure distortions.