Large-area land subsidence monitoring and mechanism research using the small baseline subset interferometric synthetic aperture radar technique over the Yellow River Delta, China

Abstract

The Yellow River Delta, the largest and most rapidly growing delta in China, has undergone severe land subsidence. However, land subsidence has not been regularly and fully measured in this large region and no consensus has been reached as to the primary cause. Here, the small baseline subset interferometric synthetic aperture radar (InSAR) method is applied to retrieve time-series deformation and the full land subsidence pattern in the Yellow River Delta. Spirit leveling data and a standard deviation map are used to verify the InSAR results and measurement accuracy. The major subsidence regions, which have a maximum subsidence rate ranging from 20 to more than 70 mm/year, cover a total of similar to 800 km(2) and are mainly concentrated in the groundwater source areas. An intimate connection of surface deformation with groundwater suggests that land subsidence is primarily caused by excessive exploitation of groundwater. In addition, comparison of the surface deformation with the precipitation record indicates that the seasonal land subsidence correlates with the rainfall rate, with a lag time of around 1 to 2 months between the precipitation peak and the minimum land subsidence displacement. The results provide new insights into land subsidence mechanisms in the Yellow River Delta. A key policy priority should, therefore, be to plan for controlling anthropogenic activities and better management of groundwater. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)