Monitoring A Time-Series Of Land Subsidence In Busan, Korea Using Space-Based Multi-Temporal Sar Observations

Monitoring of land subsidence is important to protect invaluable lives and properties. Although terrestrial observations such as Global Positioning System (GPS) survey can provide very accurate surface's displacement at a point with very high temporal resolution, it has limitation to apply for observation of vast areas. Differential radar interferometry enables us to retrieve high spatial surface's deformation map with Synthetic Aperture Radar (SAR) observations. Especially we can calculate a time-series of surface's deformation using the Small BAseline Subset (SBAS) approach reducing atmospheric artifact and topographic errors with multi-temporal SAR observations. In this study, the SBAS technique has been applied to monitor possible land subsidence in Busan, South Korea with L-band ALOS PALSAR observations. Total 19 SAR images were acquired from 15-Sep-2007 to 24-Dec-2010 with geometric baseline (from-2832 to 1855 meters). We selected 30 points which are showing significant subsidence signals for statistical analysis. The preliminary result shows land subsidence with average velocity rate of -4.09 +/- 0.65 cm/year at line of sight (LOS) direction.