Antarctica's secular motion is thought to be almost everywhere governed by horizontal rigid plate rotation plus three-dimensional deformations due to past and present changes in ice ocean loading, known as glacial isostatic adjustment (GIA). We use geodetic data to investigate deformation following the 1998 M ~8.2 Antarctic intraplate Earthquake and show sustained three-dimensional deformation along East Antarctica's coastline, 600 km from the rupture location. Using a model of viscoelastic deformation, we are able to match observed northward velocity changes, and either east or height, but not all three directions simultaneously, apparently partly due to lateral variations in mantle rheology. Our modeling predicts that much of Antarctica may still be deforming, with further deformation possible from the 2004 M 8 Macquarie Ridge Earthquake. This previously unconsidered mode of Antarctic deformation affects geodetic estimates of plate motion and GIA; its viscous nature raises the prospect of further present-day deformation due to earlier Great Earthquakes.

Item Type:	Refereed Article
Keywords:	postseismic deformation, Antarctica, GPS, DORIS
Research Division:	Engineering
Research Group:	Geomatic Engineering
Research Field:	Geodesy
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Earth Sciences
UTAS Author:	King, MA (Professor Matt King)
UTAS Author:	Santamaria-Gomez, A (Dr Alvaro Santamaria-Gomez)
ID Code:	106795
Year Published:	2016
Funding Support:	Australian Research Council (FT110100207)
Web of Science® Times Cited:	11
Deposited By:	Geography and Spatial Science
Deposited On:	2016-02-22
Last Modified:	2017-10-24
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