Vertical land motion rates for the years 2007 to 2020 for the North and South Carolina coasts

Previously existing Synthetic Aperature Radar (SAR) data were mined to generate a seamless map of vertical land motion (VLM) for an up to approximately 100-km-wide strip along the coasts of North and South Carolina. Multiple overlapping frames from ALOS and Sentinel-1A/B satellites were used to cover the entire area. We applied multitemporal InSAR processing to each frame in each viewing geometry to generate an extensive set of high-quality interferograms considering the spatial and temporal baselines. A Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) of 1-arcsecond (~30 m) spatial resolution (Farr and others, 2007) and precise satellite orbital information was used to calculate and remove the effect of topographic phase and flat earth correction (Franceschetti and others, 1999). The wavelet-based InSAR, an advanced multi-temporal SAR interferometric algorithm, was applied to reduce environmental artifacts and constrain temporally variable deformation fields (Shirzaei, 2013; Shirzaei and others, 2017). A suite of wavelet-based filters (Shirzaei and others 2012; Shirzaei, 2013) and atmospheric models (Yu and others, 2017, Yu and others, 2018) was used to reduce the residual topography-correlated component of the atmospheric phase delay and spatially uncorrelated DEM error. The set of corrected interferograms was inverted using a reweighted least-squares estimation to generate deformation time-series and velocities along the line-of-sight (LOS) direction. This operation was applied to all frames separately, then the data in the overlap zones of adjacent frames were used to perform an affine transformation and to obtain a seamless map of LOS displacement velocities for each viewing geometry (Blackwell and others, 2020; Ojha and others, 2018). Assuming a constant long-term velocity, a least-squares joint inversion was applied to combine the LOS velocity fields with observations of horizontal displacement velocity at the location of GNSS stations, which allowed for resolving the 3D deformation field at high resolution and mm/yr-level precision (Blackwell and others, 2020; Ojha and others, 2018). To translate estimated vertical deformation rates into a continental framework, vertical velocities of GNSS stations, calculated in IGS14 were used (Blewitt and others, 2013), followed by an affine transformation (including a shift, a scale factor, and two rotations) to transfer the estimated VLM into IGS14 (Blackwell and others, 2020; Ojha and others, 2018).

Edits were made to correct spelling in author name. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. (scochran@usgs.gov)

Edits were made to correct the Time Period of Content ending date from 20211231 to 20201220 and the associated date range in the title from “Vertical land motion rates for the years 2007 to 2021…” to “Vertical land motion rates for the years 2007 to 2020…”. Within the abstract section, the date range of the Sentinel-1A/B data was corrected from 2014-2021 to 2015-2020, the resolution was updated from “~75 m” to “approximately 50-75 m”, and the term “uplift” added to clarify that the VLM data include both rates of land subsidence and uplift. The above date corrections were also applied within the lineage section, to the ending date of the Sentinel-1A/B source data and to the beginning date of the ALOS data. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. (afoxgrover@usgs.gov )