ESTIMATION OF LAND SUBSIDENCE IN THE MEKONG DELTA AND ITS SURROUNDING AREAS

DOI: 10.18173/2354-1059.2021-0059

Tóm tắt

Land subsidence becomes a trouble for the different regions of the Mekong delta, where many places will be severely affected by sea-level rise in the context of climate change. Land subsidence could amplify this situation by inducing interactive hazards such as submerged land and saline intrusion, etc. Mapping the spatial distribution of land subsidence become a crucial task, and the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) approach was applied to 120 Sentinel-1A images within three scenes, captured from October 2016 to October 2020 with the interval of 36 days between two consecutive images. This approach allows mapping ground displacement by continuously extracting deformation signals and estimating the position of targets that persistently scatter radar beams. The average velocity map shows that eight main subsidence areas in the Mekong delta have been affected in recent years with the maximum velocity of -39.61 mm year-1 and the cumulative displacement ranging from 60 to 100 mm in the Line Of Sight (LOS) direction over four years. The validation using 40 Sentinel-1B images, captured in identical periods indicates a consistent result in comparison with the one issued from Sentinel-1A. These pieces of knowledge are essential for improving both citizen’s life and reducing the impact of land subsidence on the natural environment.