Intraplate deformation and strain partitioning across the northern Yangtze Craton constrained by a dense GNSS network in Hubei, central China

The northern margin of the Yangtze Craton and the adjacent Qinling–Dabie orogenic belt form a key intraplate deformation zone in central China, where far-field stresses from the India–Eurasia collision are partitioned. High-resolution geodetic constraints on present-day crustal deformation in this region have remained scarce. We processed up to 28 years of GNSS observations from a dense network of 136 stations using the Bernese GNSS software with a unified double-difference strategy. The resulting three-dimensional velocity field, referenced to the stable Eurasian plate, reveals horizontal motions of 4.3–8.7 mm/a directed southeastward, with negligible internal deformation, indicating quasi-rigid behavior of the craton interior. Vertical velocities range from −2.7 to 2.1 mm/a and present a spatial contrast: uplift of the Qinling–Dabie belt and the western mountainous margin at 1–2 mm/a, and subsidence of the Jianghan Basin up to 2.7 mm/a, with the highest rates concentrated along the Yangtze River corridor and areas of intensive groundwater extraction. Vertical noise analysis indicates that a white-plus-flicker noise model best describes the time series, yielding velocity uncertainties 1.5–2.5 times larger than white-noise-only formal errors. Under this model, most stations in the uplift and subsidence zones show statistically significant vertical velocities at the 95% confidence level. Seasonal signals exhibit vertical annual amplitudes roughly twice the horizontal, with phase peaks corresponding to thermoelastic, monsoonal, and hydrological forcings. The maximum shear strain rate of 5.3 × 10 -8 /a occurs in the Badong–Zigui area and coincides with moderate seismicity. Historical earthquakes tend to cluster along the margins of high-shear-strain zones and within compressional-to-extensional transition areas. The dense GNSS velocity field provides a geodetic reference framework for future crustal deformation monitoring and seismic hazard assessment in this intraplate setting.