Sentinel-1 Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) for Long-Term Remote Monitoring of Ground Subsidence: A Case Study of a Port in Busan, South Korea

Reclamation has allowed rapid land expansions for economic zones, residential areas, airports, industrial parks, and seaports. Meanwhile, the reclaimed lands often pose a risk of ground subsidence, jeopardizing functions of aboveground infrastructures, buildings, and facilities and threatening human lives. Therefore, it is critical to systematically monitor and manage the reclaimed lands after construction and minimize geohazard risks. This paper presents a case study on long-term remote monitoring of ground subsidence in reclaimed land using satellite synthetic aperture radar (SAR) data and the Persistent Scatterer Interferometric SAR (PS-InSAR) technique. The case study explores the excessive and persistent ground subsidence in Busan New Port, South Korea, which occurred since 2007. We employ large stacks of Sentinel-1 data acquired from the ascending and descending tracks for reliable estimation of ground subsidence and utilize the hyperbolic model, providing an updated prediction tool. A benchmarking and media fact-checking approach consistently supports our PS-InSAR analysis results. The time-series results show that the maximum subsidence rate is approximately -85 mm/yr along the radar line-of-sight (LOS). PS-InSAR can assist in saving expensive and laborious mapping and operational field-survey services and offers essential guidance for the next phase of future construction of Busan New Port.