Application of sar images for evaluating the ground subsidence in Nam Sai Gon using the dinsar technique

Abstract

Synthetic Aperture Radar (SAR) images have widely utilized in environmental monitoring as well as geological hazards (subsidence, landslide,...), however, this is still a quite new technology in Vietnam. Therefore, the main purpose of this study is to introduce the DlnSAR technique and effects to SAR images analysis processing. Nam Sai Goti has been selected as the study area, which has been strong subsidence process due to geological characteristic and urbanization. In this work, the SAR images are collected from Sentinel-1 satellite and analyzed in open source SNAP software through the Differential Interfero metric SAR (DlnSAR) technique. The results show the subsidence values in the 3, 6 and 12 months with the value from 010cm in 6 months and 2.5-15cm in 12 months. Through the analysis of noise areas, the results can be affected by the tide factor. For detailed assessment, 28 sites of subsidence survey in the study area were collected. This results indicate that the anomalous areas (bridge, main road) have large subsidence.