Unveiling disparities: a surface deformation analysis influenced by the human activities and natural conditions in the middle Yarlung Zangbo River Valley

The middle reaches of Yarlung Zangbo River Valley lie at the boundary zone between the Eurasian Plate and the Indian Plate. Geological disasters caused by the deformation of its surface pose a great threat to people's production and life. Using Sentinel-1A imagery (2017–2022), this study applied SBAS-InSAR and discrete wavelet transform to analyze surface deformation patterns and trends in the typical area of the middle reaches of the Yarlung Zangbo River Valley. It further unveiled disparities in surface deformation under the influence of human activities and natural conditions. Results indicated that the deformation rates from 2017 to 2022 ranged from −59.38 to 25.50mm/a. It exhibited a slight uplift trend, with the northern section being relatively stable, while the southern part showed uneven deformation. Seasonal subsidence is pronounced, with greater deformation in spring and summer compared to autumn and winter. Among human activities, mining had the most significant impact on surface deformation, reaching −4.29mm/a, followed by agriculture and road construction at −2.60mm/a and −1.40 mm/a, respectively. In terms of natural factors, precipitation was identified as a key driver of surface deformation, with land cultivation, river erosion, and surface load all closely related to precipitation levels. Overall, natural conditions, and human activities had alternating effects on surface evolution. Most of the area showed a slight upward changing trend, except in some areas severely disturbed by human activities. These findings provided crucial insights for developing strategies to address surface deformation in the Yarlung Zangbo River Valley. • Unveiling impact of human and natural factors on surface deformation with SBAS-InSAR. • Reveals spatial deformation at the Eurasian–Indian Plate boundary. • Mining is top human cause of subsidence, ahead of agriculture and infrastructure. • Precipitation amplifies natural deformation, affecting crops and rivers.