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Novel Quantification of Shallow Sediment Compaction by GPS Interferometric Reflectometry and Implications for Flood Susceptibility
Author(s) -
Karegar Makan A.,
Larson Kristine M.,
Kusche Jürgen,
Dixon Timothy H.
Publication year - 2020
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 - 10.1029/2020gl087807
Subject(s) - geology , global positioning system , reflectometry , tide gauge , flood myth , sediment , compaction , sedimentation , sea level , interferometry , hydrology (agriculture) , geodesy , geomorphology , oceanography , geotechnical engineering , time domain , geography , telecommunications , physics , archaeology , astronomy , computer science , computer vision
Estimates of flood susceptibility and land loss in the world's coastal regions depend on our knowledge of sea level rise (SLR) from increases in ocean mass and volume, as well as knowledge of vertical land motion. Conventional approaches to the latter include tide‐gauge and Global Positioning System (GPS) measurements relative to well‐anchored monuments few meters below the surface. However, in regions of rapid Holocene sedimentation, compaction of this material can add a significant component to the surface lowering. Unfortunately, this process has been difficult to quantify, especially for the shallowest material above the monument. Here we use a new technique, GPS interferometric reflectometry, to estimate the rate of this process in the Mississippi Delta and the eastern margin of the North Sea. We show that the rate of shallow compaction is comparable to or larger than the rate of global SLR, adding 35% and 65%, respectively, to the rate of relative SLR by 2100.