42 Geophysics/Geodynamics (Posters)

Added due to amt of discipline abstracts submitted.

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

High-Resolution Mapping of Local Vertical Land Motion Along the Northeastern Coast of South Carolina

Paper number: 42-5
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Along the U.S. East Coast, rates of relative sea-level rise vary greatly due to differences in ocean dynamics and local to regional subsidence. Within the southeastern region, only a few accurate modern data points are located between southern North Carolina and Charleston, South Carolina. In this coastal stretch lies Myrtle Beach, one of the fastest growing metropolitan areas in the country. The modern rate of relative sea-level rise in this geographic region has been significantly higher over the past century (3.36 ± 0.47 mm/yr) compared to Charleston (3.51 ± 0.2 mm/yr) and Wilmington (2.79 ± 0.3 mm/yr), possibly due to undifferentiated effects of land subsidence in the Winyah Bay region (NOAA). This study uses Real-Time Kinematic (RTK) GPS to remeasure surface elevations at a network of historic benchmarks across South Carolina’s northern coast, generating a high-spatial-resolution dataset of local vertical land motion (VLM) from Little River to Georgetown. Subregions were defined by grouping geographically close benchmarks for more detailed analysis of the study area. 

 

Results of these regional analyses show an average VLM rate of -0.13 mm/yr. When compared to existing InSAR (USGS) and a long-term continuous GPS measurement database (Nevada Geodetic Laboratory), our measured rates are relatively consistent along subregions, with those along the coast including North Myrtle Beach, Murrells Inlet, and Pawleys Island being less variable than the inland sites Bucksport and Georgetown. Heterogenous stratigraphy and tectonic structures may drive spatially differentiated rates of VLM across inland sub-regions. Quantifying localized VLM rates clarifies the drivers of sea-level rise, enabling communities to better allocate resources and plan for future flooding and land-use changes.  

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411762

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.