Authors / CoAuthors
Zhao, S.
Abstract
The Global Positioning System (GPS) and the Gravity Recovery and Climate Experiment (GRACE) have been used to respectively determine the Earth's surface deformation and gravity changes associated with Glacial Isostatic Adjustment (GIA), which is caused by ongoing stress release of the viscoelastic mantle after removal of the Late Pleistocene ice-sheets. Here we present a joint inversion analysis of the GPS derived radial (vertical) deformation and GRACE derived gravity changes in North America to examine whether the ice-sheets (ICE-5G) and earth models can fit the satellite based observations. The results from a three-layer earth model give a lithosphere thickness of 120~150km, an upper-mantle viscosity of 2.1~3.5 × 10**20 Pa s, and a lower-mantle viscosity of 1.3~1.7 × 10**21 Pa s. More sophisticated models such as introducing a transition zone of 400-670km are not fully resolved with current datasets because there is no significant improvement in fitting observations. Tests of modifying ICE-5G show that a reduction of ice thickness by ~20% in the area west of Hudson Bay and an increase by ~40% in the southeast (Quebec region) are required to fit both observed vertical deformation and gravity changes.
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nonGeographicDataset
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74054
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- External PublicationAbstract
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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2012-05-07T00:00:00
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