Monitoring the Land Subsidence Area in a Coastal Urban Area with InSAR and GNSS

Abstract

In recent years, the enormous losses caused by urban surface deformation have received more and more attention. Traditional geodetic techniques are point-based measurements, which have limitations in using traditional geodetic techniques to detect and monitor in areas where geological disasters occur. Therefore, we chose Interferometric Synthetic Aperture Radar (InSAR) technology to study the surface deformation in urban areas. In this research, we discovered the land subsidence phenomenon using InSAR and Global Navigation Satellite System (GNSS) technology. Two different kinds of time-series InSAR (TS-InSAR) methods: Small BAseline Subset (SBAS) and the Permanent Scatterer InSAR (PSI) process were executed on a dataset with 31 Sentinel-1A Synthetic Aperture Radar (SAR) images. We generated the surface deformation field of Shenzhen, China and Hong Kong Special Administrative Region (HKSAR). The time series of the 3d variation of the reference station network located in the HKSAR was generated at the same time. We compare the characteristics and advantages of PSI, SBAS, and GNSS in the study area. We mainly focus on the variety along the coastline area. From the results generated by SBAS and PSI techniques, we discovered the occurrence of significant subsidence phenomenon in the land reclamation area, especially in the metro construction area and the buildings with a shallow foundation located in the land reclamation area.

Regression Analysis of Subsidence in the Como Basin (Northern Italy): New Insights on Natural and Anthropic Drivers from InSAR Data

“…To improve the spatial density of radar targets in non-cultivated or desert areas with moderate coherence due to small scattering objects, other techniques using Distributed Scatterers (DS) were then proposed, such as the Small BAseline Subset (SBAS) [17] and SqueeSAR [18] algorithms (for an overview, see [15]). Since their introduction, InSAR techniques have been largely applied for monitoring land subsidence, both in Italy [5,8,11,[19][20][21][22][23][24][25][26][27] and worldwide [2,6,12,13,[28][29][30][31][32][33][34][35][36]. The InSAR techniques allow the reconstruction of the deformation history of radar targets (PS) and for information about ground settlements to be obtained with high precision [23].…”

DInSAR based land deformation detection in the karst landscape of Gunung Sewu

“…Further research should be conducted to identify a few factors affected the differentiation of land deformation rate in the karst landscape of Gunung Sewu. Besides of that, utilising of GNSS CORS as data source is needed to consider, it would improve the accuracy of land deformation detection and enrich the land deformation study, not merely limited on vertical deformation, yet also horizontal deformation [18,19,45,46].…”

Spatio-Temporal Assessment of Land Deformation as a Factor Contributing to Relative Sea Level Rise in Coastal Urban and Natural Protected Areas Using Multi-Source Earth Observation Data

“…Particularly, coastal low-lying regions will be affected, and their land will be decreased due to coastal erosion and inundation [1,2]. In the early 1990s, 33.5% of the global population lived within In this framework, MT-InSAR approaches were extensively and successfully exploited to investigate coastal ground deformation [32][33][34]. These techniques, such as permanent scatterers (PSs) [35], SBAS [36], and interferometric point target analysis (IPTA) [37] use a medium-to-large dataset of SAR images acquired at different times over the observed area to follow the temporal evolution of a deformation phenomenon, retrieving the mean deformation rate and the time series for each point target.…”