In the past, the free-air gradient −308.6 × 10⁻⁸ s⁻² was used as the vertical gravity gradient of the measuring point in gravity data processing, which resulted in inaccurate instrument height corrections. To investigate the influence of using the vertical gravity gradient, theoretical gradients of the Jinzhai baseline field in the Dabie Mountains were calculated using DEM data and WGM2012 gravity anomaly data. Adjustment results were compared with those using the free-air gradient. Using the theoretically calculated vertical gravity gradient correction improved the scale factor calibration precision by an average of 0.00007. The average precision of gravity adjustment results under different datum controls increased from 2.23 × 10⁻⁸ m/s² to 1.45 × 10⁻⁸ m/s². In a single-datum control adjustment, the maximum effect of the actual vertical gravity gradient on datum transfer is 8.7 × 10⁻⁸ m/s², while the effect without it is as low as 9.0 × 10⁻⁸ m/s² and as high as 27.5 × 10⁻⁸ m/s². In a multi-datum system, using the actual vertical gravity gradient yields the best results. Even with the three-datum control adjustment, the average effect of the free-air gradient correction on the results reaches 3.9 × 10⁻⁸ m/s². Therefore, incorporating measured or theoretically calculated vertical gravity gradients into gravity data processing is essential for significantly enhancing its accuracy and precision.

On March 28, 2025, an M_W7.7 earthquake struck Myanmar, with the epicenter located in the central segment of the Qinghai–Xizang–Yunnan–Myanmar–Indonesia η-type structure. This region hosts a series of active faults, including the right-lateral Sagaing Fault and the Red River Fault in southwestern Yunnan. Based on the fault geometry model published by Zhang et al. and the Crust1.0 layered medium model, this study simulates the co-seismic and post-seismic Coulomb stress changes at depths of 5, 10, and 15 km on the main fault zones within the study area. The results indicate that the earthquake was dominated by Coulomb stress unloading, with localized loading observed at the northern and southern ends of the rupture. On the Sagaing Fault, Coulomb stress changes were dominated by unloading: average decreases ranged from −2.4 to −4.7 bar across all depths and timescales, indicating a low likelihood of large-scale rupture on that fault. However, in the northern segment of the rupture, localized stress loading exceeded the critical threshold of 0.1 bar, suggesting a possible enhancement of local seismic hazard. In southwestern Yunnan, co-seismic Coulomb stress loading at all depths ranged from −0.37 × 10⁻² to 1.8 × 10⁻² bar. Post-seismic stress changes were minor, with a maximum of 3.2 × 10⁻³ bar. These results imply that the M_W7.7 event induced only subtle adjustments to the long-term tectonic stress field in southwestern Yunnan; nevertheless, the presence of stress-loading regions within seismic gaps warrants continued attention to potential hazard.

Previous studies show that the calculated loading effects from global ocean tide models do not match actual measurements of gravity attraction and loading effects in Southeast Asia. In this paper, taking advantage of a unique network of gravity tidal stations all over the Chinese mainland, we compare the observed and modeled tidal loading effects on the basis of the most recent global ocean tide models. The results show that the average efficiencies of the ocean tidal loading correction for O₁, K₁, M₂ are 77%, 73% and 59%, respectively. The loading correction efficiencies using recent ocean tidal models are better than the 40 years old Schwiderskis model at coastal stations, but relative worse at stations far from ocean.