Monitoring and predicting land subsidence associated with land creation over Yan’an New City (China) by using time series InSAR technique

Abstract

New flat land was created in Yan’An (China) through bulldozing mountains and filling valleys for subsequent urban construction. This creation may cause severe environmental problems, with major concern on the large-scale land subsidence. However, large-scale high-precision monitoring and predicting works haven’t been conducted in this region. Based on this background, time series Syntenic Aperture Radar Interferometry (InSAR) technique is adopted in this regon to process 165 C-band Sentinel-1A data with purpose of mapping land subsidence associated with land creation. The result shows that clear subsidence is observed in the filling area, where the maximum subsidence reaches to 6 cm/y. Meanwhile, phenomenon of alternate uplift and subsidence reflects the complexity of deformation due to the land creation. When connecting subsidence with the filling thickness, building distribution and local precipitation, it is found that the magnitude of subsidence in YANC is controlled by filling thickness and precipitation. The Asaoka model was used to predict the land subsidence and indicated that the subsidence will be stable in the future five years. Our observation may have significant implications for effective land creation, urbanization planning and land subsidence management decision, where mountains are bulldozed to increase the space available for urban development.