Modeling Saline Mudflat and Aquifer Deformation Synthesizing Environmental and Hydrogeological Factors Using Time-Series InSAR

Clarifying the surface and subsurface deformation is important for protecting the infrastructures attached to the ground and reasonably exploiting the underground resources. This article presents an improved deformation model combining environmental factors (i.e., precipitation and temperature) with hydrogeological parameters to separate the saline-soil deformation from the aquifer deformation over Qarhan Salt Lake, China. First, the vertical ground deformation was derived by 119 ascending and 113 descending synthetic aperture radar images of Sentinel-1A collected from July 2015 to May 2020. Subsequently, we estimated the deformation components derived from temperature, precipitation, seasonal oscillation, magnitude, and decay coefficient of the hydrodynamic function by the proposed deformation model. The estimated deformation and decay coefficient maps pinpoint the existing and previously unknown faults. Next, we compared our proposed prototype with the sinusoidal and exponentially decaying model to present the reliability and efficiency in separating the deformation components and estimating the decay coefficient. Finally, we collected the stratigraphic data from 50 drilling wells to validate our model results by simulating the cumulative silt and clay layers (aquitard) thickness utilizing the Ordinary Kriging interpolation method. Findings show that by quantifying the aquitard thickness in the drilling wells, there is a strong relationship in the spatial distribution between cumulative thickness and the decay coefficient. The results suggested that both the decay coefficient and the aquitard-layer thickness can be used as the vital parameters to partition hydrogeological units, which provides an opportunity to detect and mitigate the potential geological hazards in the saline mudflat.