Use of geodetic observations for regional monitoring of vertical land motion along Eastern Seaboard United States

Relative sea-level rise (RSLR) is a combination of the rising sea and subsidence or uplift of the land. Identifying and quantifying the processes responsible for RSLR is important for anticipating coastal hazards and planning purposes. Along much of the US east and Gulf coast vertical land motion is the dominant driver to RSLR. Various geophysical processes contribute to vertical land motion acting at different spatial temporal scales, including those as result of Glacio-Isostatic Adjustment, tectonic deformation related to plate motion, and sediment compaction as a result of groundwater and oil withdrawal. Especially the latter leads to localized deformation signals often not captured by the sparsely distributed (50-100 km) GNSS network.

In this study, we take advantage of high-resolution Sentinel-1 InSAR observations to complement the GNSS network. We use publicly available standard InSAR products, provided by the JPL Advanced Rapid Imaging and Analysis (ARIA) project, to generate a 90 m resolution vertical rate map spanning 700 km of the US east coast (from South Carolina to Virginia) extending up to 150 km inland.

We applied advanced time-series InSAR processing in combination with tropospheric noise corrections, estimated from weather model outputs provided by NOAA, to estimate long-term vertical displacement rates. We use GNSS to correct the InSAR for residual long-wavelength errors and propagate uncertainties accordingly. We find spatial variation of vertical land-motion, with hotspots around for urban areas.