Satellite-based measurement of ground displacements for the coastal region of Charleston, South Carolina

Abstract

SNAP-6 DInSAR analysis of Sentinel-1 SAR images acquired during a 2-month time frame when no significant uplift/subsidence events occurred provides the first known baseline DInSAR data for the Charleston, South Carolina, area. DInSAR measurements during a 72-day time frame had substantial bias throughout the region, with variability a strong function of the level of vegetation present. Specifically, results for (a) urban-built areas show low variability (<0.27 cm) with a bias/offset ranging from −25 to 16 cm, (b) nearby Francis Marion National Forest (FMNF) shows much high variability (1.67 to 10.52 cm) with bias/offset from −44 to 22 cm, and (c) mixed urban-forest and other vegetated areas in the region have variability (1.5 to 2.5 cm) and bias/offset (−15 cm to 15 cm) that fall between these ranges. Taken together, the satellite-based measurements indicate the need for integration of available local GPS and DInSAR measurements, as well as placement of additional persistent scatterer sites in the outlying regions.