Abstract
Wuhan, the largest city in central China, has experienced rapid urban development leading to land subsidence as well as environmental concerns in recent years. Although a few studies have analyzed the land subsidence of Wuhan based on ALOS-1, Envisat, and Sentinel-1 datasets, the research on long-term land subsidence is still lacking. In this study, we employed multi-temporal InSAR to investigate and reveal the spatiotemporal evolution of land subsidence over Wuhan with ALOS-1, Envisat, and Sentinel-1 images from 2007–2010, 2008–2010, 2015–2019, respectively. The results detected by InSAR were cross-validated by two independent SAR datasets, and leveling observations were applied to the calibration of InSAR-derived measurements. The correlation coefficient between the leveling and InSAR has reached 0.89. The study detected six main land subsidence zones during the monitoring period, with the maximum land subsidence velocity of −46 mm/a during the 2015–2019 analysis. Both the magnitude and the extent of the land subsidence have reduced since 2017. The causes of land subsidence are discussed in terms of urban construction, Yangtze river water level changes, and subsurface water level changes. Our results provide insight for understanding the causes of land subsidence in Wuhan and serve as reference for city management for reducing the land subsidence in Wuhan and mitigating the potential hazards.
Highlights
Because of highly compressible soils and significant human activity, land subsidence has been a problem for many cities [1,2,3]
The PS-InSAR method was applied to the 19 images acquired by ALOS-1 and the SBAS-InSAR method was used for the 104 images acquired by Sentinel-1 over Wuhan
This study presents an InSAR time series investigation of land subsidence for the periods 2007–2010 and 2015–2019 in Wuhan
Summary
Because of highly compressible soils and significant human activity, land subsidence has been a problem for many cities [1,2,3]. One of the largest cities in China, has experienced multiple geological hazards in recent years because of the complex geological setting and anthropogenic activities. The main geohazards include surface sinking, landslides, collapse of unstable rock masses, debris flows, and land subsidence. The human casualties and property damage caused by these geo-hazards necessitates urban subsidence monitoring to preserve the safety and integrity of infrastructure, and to responsibly manage urban planning [6]. At least 29 geo-hazards associated with surface sinking have been recorded in Wuhan from 1977 to 2014 [7]. Previous studies show that Wuhan’s land subsidence resulted from: (1) over-extraction of groundwater,
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