Zhengzhou, China, has witnessed significant land subsidence and deformation following the extreme rainstorm on July 20, 2021. A recent study utilized advanced techniques, including Multi-temporal Synthetic Aperture Radar Interferometry (MT-InSAR), eXtreme Gradient Boosting (XGBoost), and hydrogeological analysis, to assess and predict trends related to land subsidence comprehensively.
This research identified three primary subsidence zones within Zhengzhou, with the most severe areas recorded at northern Zhongmu, northwest Xingyang, and western Gongyi. Specifically, subsidence rates reached as high as -28 mm/year, with the updated data reflecting the pressing issue of ground motion exacerbated by human factors, particularly groundwater extraction and urban development.
The analysis revealed notable uplift zones as well, particularly within the central districts of Zhengzhou and at the Xinzheng Airport, recording uplift rates of 13 mm/year and 12 mm/year respectively. This juxtaposition of subsidence and uplift highlights the varied geological dynamics occurring as urbanization continues to reshape this rapidly growing city.
The accuracy of the MT-InSAR-derived results was validated against field data, yielding impressive figures, such as the overall root-mean-square error (RMSE) of 2.2 mm/year and R-squared value of 0.948. This accuracy establishes a reliable foundation for future predictions and urban planning interventions.
Key factors influencing land deformation were analyzed using the XGBoost method, with road density and precipitation identified as the most pronounced contributors. The relationship is increasingly significant in subsidence-prone areas, where heavy rainfall leads to higher subsidence rates, indicative of the urgent need for strategic groundwater management.
These results not only add to the body of knowledge on urban land subsidence but also provide actionable insights for municipal authorities to implement effective measures to mitigate future risks associated with land deformation.
The study’s geographic pattern analysis indicated a northeastward trend, highlighting the evolution of land deformation from 2018 to 2022, showcasing both the physical changes and the related influences of human activity. On the surface, the increased rates suggest increased structural load and subsurface instability, exacerbated by intensive urbanization efforts over the last two decades.
Researchers deployed MT-InSAR to gather extensive data across Zhengzhou, applying numerous state-of-the-art techniques to comprehend the factors influencing this urban geography. By integrating satellite data with local observations, the team successfully mapped the varying deformation impacts over time, offering predictive capabilities for future urban planning.
Overall, this research reconfirms the need for interdisciplinary approaches combining advanced remote sensing technologies with traditional hydro-geology and civil engineering perspectives to address modern urban challenges effectively. Going forward, additional focus will be necessary on conservation efforts to balance urban growth with sustainable land management practices to preserve both infrastructure integrity and environmental resilience.