DInSAR-based estimation of subsidence rate along an UMRT line in Hanoi

Summary Construction of the Urban Mass Rapid Transit (UMRT) lines in Hanoi have been considered since the 90s of the last century, and it starts to be conducted now to meet the increasing transport demands of the people living in this capital city of Vietnam. There is a concern that whether or not land subsidence due to groundwater extraction would affect the UMRT lines. Besides the conventional monitoring of subsidence, newer methods using satellite images such as DInSAR should be considered and applied. One of the limitations of DInSAR application is effect of decorrelation noises on quality of Interferograms. In this paper, the factors that may affect the DInSAR results were discussed, including general decorrelation noise and the selection of reference point. A case study for Hanoi city was conducted by two methods; DInSAR and one-dimensional finite element (FEM) consolidation analysis, to estimate the subsidence rate along the UMRT line No. 2. The results of this study showed a good match and consistency in the results obtained by these two methods. Consequently DInSAR is recommended for further land subsidence analysis for other targets in the urban area of Hanoi.