Multi-Frequency Synthetic Aperture Radar Observations to Explore Ground Subsidence.

Ground subsidence, particularly in urban environments, poses a significant geohazard risk to private and public infrastructure. The subsidence can be caused by anthropogenic activity, such as excessive groundwater pumping, underground excavation, land reclamation, or geological forces (e.g., slow fault movement and earthquakes, and volcanic activity). Although terrestrial measurements using a Global Satellite Navigation Systems ( GNSS) or in-situ leveling survey provide accurate ground displacement information with a variable temporal resolution, such measures are limited due to their sparse spatial sampling. Furthermore, terrestrial measurements are associated with a high cost to survey the ground deformation. We present time-series analyses of ground subsidence in the southeastern part of Korea using multi-frequency synthetic aperture radar (SAR) observations. We investigate if ground subsidence can be retrieved with recent SAR observations that will be processed using several approaches for Interferometric SAR (InSAR) time-series, including Small Baseline Subset (SBAS) and Persistent Scatterer Interferometry (PSI) techniques. Preliminary results using COSMO-SkyMed and ALOS-2 SAR observations will be presented.