Incomplete separability of Antarctic plate rotation from glacial isostatic adjustment deformation within geodetic observations

Geodetic measurements of Antarctic solid Earth deformation include signals from plate rotation and glacial isostatic adjustment (GIA). Through simulation, we investigate the degree to which these signals are separable within horizontal GPS site velocities that commonly define plate rotation estimate...

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Bibliographic Details
Published in:Geophysical Journal International
Main Authors: King, MA, Whitehouse, PL, van der Wal, W
Format: Article in Journal/Newspaper
Language:English
Published: Blackwell Publishing Ltd 2016
Subjects:
Engineering
Geomatic Engineering
Geodesy
Antarctic
East Antarctica
Antarc*
Antarctica
Online Access:https://doi.org/10.1093/gji/ggv461
http://ecite.utas.edu.au/104895
Description
Summary:Geodetic measurements of Antarctic solid Earth deformation include signals from plate rotation and glacial isostatic adjustment (GIA). Through simulation, we investigate the degree to which these signals are separable within horizontal GPS site velocities that commonly define plate rotation estimates and that promise new constraints on models of GIA. Using a suite of GIA model predictions that incorporate both 1-D and 3-D Earth rheologies, we show that, given the present location of GPS sites within East Antarctica, unmodelled or mismodelled GIA signal within GPS velocities produces biased estimates of plate rotation. When biased plate rotation is removed from the GPS velocities, errors as large as 0.8mm yr −1 are introduced; a value commonly larger than the predicted GIA signal magnitude. In the absence of reliable forward models of plate rotation or GIA then Antarctic geodetic velocities cannot totally and unambiguously constrain either process, especially GIA.

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