A Preliminary Study on the Use of Differential Interferometric Synthetic Aperture Radar (DInSAR) for Ground Subsidence Assessment

Ground subsidence is a major engineering problem in urban areas where population growth and rapid urban development are taking place. Central Florida is also known as the karst area with its unique hydrogeological setting, posing potential ground instability such as sinkhole-induced subsidence and ground settlement due to urban construction and development. Monitoring of ground subsidence can help not only mitigate its negative impacts in many engineering ways but also enhance the related risk management. With recent advances in remote sensing technology, Interferometric Synthetic Aperture Radar (InSAR) can be a promising tool to measure and monitor ground subsidence. The goal of this study is to explore the feasibility of InSAR for the ground subsidence assessment. Particularly, we investigated the spatial distribution of ground subsidence in the Orlando metropolitan area and its near vicinities over two different times. For this, the Differential Interferometric Synthetic Aperture Radar (DInSAR) method was applied to develop a ground subsidence map between May 8, 2018, and May 9, 2020, using the European Space Agency (ESA) Sentinel-1 SAR images. The results show that the study area is clearly showing a cumulative ground movement trend of varying degrees, with -22.9 cm (subsidence) and +2.0 cm (uplift), over the past two years. It also shows that the magnitude of ground subsidence in this area was largely related to land use and development activities. This study demonstrates that the multitemporal InSAR processing technique is capable of high-precision monitoring of ground subsidence in urban areas for engineering purposes.