Three decades evolution of land subsidence driven by anthropogenic activities in the Yellow River Delta (YRD) from continuous SAR interferometry

The Yellow River Delta (YRD) has experienced severe subsidence due to anthropogenic activities. However, no study has resolved continuous deformation and investigate its mechanism across a three-decade timeframe from InSAR perspective since the early 1990s. This study proposes a Trend-Adaptive Functional Modeling and Connection method (TAFMC) for multi-sensor InSAR time series integration, with features of adaptability, robustness, and efficiency. It enables the identification of continuous deformation trends previously obscured by data gaps, thereby directly supporting the discovery of decadal deformation evolution. Second, six InSAR sensors were integrated to retrospect to the ground deformation in YRD from 1992 to 2024. The connected InSAR time series indicates three decades of subsidence, caused by deep groundwater extraction, reached up to 220 cm in Guangrao County. But the subsidence has been effectively controlled from >10 cm/yr during 1992–2021 to ∼5 cm/yr after 2021. Since 2015, an inland migration of a coastal subsidence funnel occurred due to the brine industry. Multiple small-scale subsidence funnels with rates exceeding 15 cm/yr emerged, linked to shrimp aquaculture around 2023. These findings provide comprehensive insights for the interaction between anthropogenic activities and the YRD subsidence on a decadal scale, and offer a methodological framework applicable to InSAR multi-decadal analysis in other delta regions.