This study utilized 171 Sentinel-1 images and SBAS-DInSAR to retrieve subsidence in the Yellow River Delta. Multiple results were used for cross-validation and the spatiotemporal characteristics of the subsidence and its causes in various human-impacted areas were explored. The results indicate that the northern estuary, west of Gudong Oilfield, eastern Kenli District and Guangrao Salt Field exhibit larger SR than other areas. The average SR of the four areas are −93.3, −30.5, −26.3 and −92.4 mm/yr, respectively, while the maximum ones are −255, −152.4, −144.7 and −210 mm/yr, respectively. The primary driving factors are the extraction of underground brine, oil, and groundwater. Deformations in Gudao oilfield present a significant subsidence trend from January 2019 to July 2020 with maximum accumulation of −56.3 mm (around −36.4 mm/yr), followed by slight rebound after July 2020 with maximum accumulation of −2.8 mm (around 30.7 mm/yr). In brine extraction area, significant linear subsidence occurred from January to August 2019, with varying degrees of rebound from August 2019 to March 2020, followed by a return to rapid subsidence trend. From January 2022 to August 2023, the subsidence displays different spatial distribution and magnitude as compared to that from 2019 to 2022.
Yu et al. (Sat,) studied this question.