Vertical deformation in the northeastern Tibetan Plateau based on optimized GNSS time series non-tectonic deformation model

The acquisition of high-precision GNSS vertical velocity fields constitutes a critical foundation for investigating tectonic processes. Refined modeling of non-tectonic deformations within GNSS time series is key to achieving high-precision tectonic deformation estimates. This paper utilizes GNSS observation data from 46 continuous GNSS stations and 176 campaign GNSS stations in the northeastern Tibetan Plateau margin from 2010 to 2022. Based on the differential response of soil and bedrock stations to environmental loads, non-tectonic deformation correction models are constructed for each type of station. Environmental loading datasets provided by GFZ and NASA are combined to evaluate the correction performance of different loading correction schemes on GNSS vertical time series, leading to the construction of an optimized non-tectonic deformation correction model. The results show that, after non-tectonic deformation correction, the root mean square (RMS) values of GNSS time series for 95% of the continuous stations and 83% of the campaign stations, indicating that this method effectively reduces the dispersion of the time series. The corrected time series were fitted with functions to extract a high-spatial-resolution vertical velocity field for the northeastern Tibetan Plateau margin, the results reveal the primary tectonic units and their internal vertical deformation characteristics. Marked spatial variation in vertical deformation is observed across the northeastern Tibetan Plateau margin, with the Liupanshan Fault Zone acting as a distinct boundary. The region to the west of the fault zone shows an overall slow subsidence, while the area to the east exhibits general uplift, with an average uplift rate of 1.2 mm·a−1. Notably, the Liupanshan Fault Zone shows significant local uplift, with a rate of up to 5 mm·a−1. The average subsidence rates in the Alxa block and the Qilian Mountains orogenic belt are -0.5 mm·a−1 and -1.2 mm·a−1, respectively. The Ordos block exhibits an average uplift rate of 1.0 mm·a−1. The Yinchuan Rift Basin shows the most significant subsidence, with an average rate of -1.8 mm·a−1.