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Subsidence along the Atlantic Coast of North America: Insights from GPS and late Holocene relative sea level data
Author(s) -
Karegar Makan A.,
Dixon Timothy H.,
Engelhart Simon E.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068015
Subject(s) - holocene , geology , tide gauge , sea level , subsidence , post glacial rebound , oceanography , physical geography , climatology , geomorphology , geography , structural basin
The Atlantic Coast of North America is increasingly affected by flooding associated with tropical and extratropical storms, exacerbated by the combined effects of accelerated sea‐level rise and land subsidence. The region includes the collapsing forebulge of the Laurentide Ice Sheet. High‐quality records of late Holocene relative sea‐level (RSL) rise are now available, allowing separation of long‐term glacial isostatic adjustment‐induced displacement from modern vertical displacement measured by GPS. We compare geological records of late Holocene RSL to present‐day vertical rates from GPS. For many coastal areas there is no significant difference between these independent data. Exceptions occur in areas of recent excessive groundwater extraction, between Virginia (38°N) and South Carolina (32.5°N). The present‐day subsidence rates in these areas are approximately double the long‐term geologic rates, which has important implications for flood mitigation. Tide gauge records, therefore, should be used with caution for studying sea‐level rise in this region.