Nonlinear response and hysteresis analysis of groundwater storage and surface deformation in the Dezhou area

Historically affected by land subsidence resulting from excessive groundwater withdrawal, the Dezhou region is currently experiencing a significant hydrological transition following the implementation of the South-to-North Water Diversion Project. This study retrieves Groundwater Storage (GWS) variations from April 2002 to June 2025 using data from the Gravity Recovery and Climate Experiment (GRACE)/GRACE-FO missions and the Global Land Data Assimilation System (GLDAS), and validates them against in-situ well observations. Concurrently, vertical surface deformation from 2020 to 2025 is monitored using Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR). Time-Varying Set Pair Potential (SPP) theory is integrated with the Load-Unload Response Ratio (LURR) to assess the stability and integrity of the soil structure. Furthermore, cross-correlation techniques are employed to quantify the hysteresis effect between groundwater changes and surface deformation. Results show that GWS exhibited three distinct phases: “fluctuating rise, continuous deficit, and rapid recovery.” Following a peak deficit in May 2021, GWS recovered at a rate of 4.46 mm/month. Surface deformation exhibits significant spatial heterogeneity: Qihe and Wucheng remain the primary subsidence bowls (with a maximum cumulative subsidence of approximately 150 mm), whereas Pingyuan and Xiajin exhibit uplift (with a maximum uplift of approximately 53 mm). Mechanistically, LURR anomalies observed between 2021 and 2022 indicated plastic deformation; however, post-2024 data suggest a gradual recovery of elastic energy, despite persistent risks in deep geothermal extraction zones. Hysteresis analysis reveals distinct variability: shallow sandy soils respond rapidly (lag <30 days), while deep clay layers exhibit lag times concentrated between 150 and 250 days. These findings quantify surface response mechanisms under groundwater recharge conditions, providing a theoretical basis for subsidence prediction.