Uncertainty of Approximate Relationship between GIA Induced Viscous Gravity and Radial Displacement
Jia Lulu
Wang Hansheng
Xiang Longwei
Abstract：Based on glacial isostatic adj ustment (GIA)models of different mantle viscosities,the contribution from different layers in the earth?s interior to the GIA viscous gravity perturbation rates is investigated,and the approximate relation between GIA gravity perturbation rate and uplift rate and whether it is independent of the mantle viscosity are validated in this paper. Furthermore,the Wahr?s approximate relation with the data from absolute gravimetry and global positioning system (GPS) was checked.It is found that the contribution of the lithosphere to GIA gravity perturbation rate and geoid anomaly rate is more than 86%,the contribution of the five layers under the lithosphere to GIA gravity signal is less than 14% yet.The relative difference between GIA uplift rate calculated by using approximate relation and that by the finite element method is about 1 5%, and the difference does not depend on changes in the mantle viscosity.The ratio of gravity versus uplift obtained by ground-based measurements in North America is 0.141±0.014μGal/mm,which is very close to 0.154μGal/mm of Wahr?s theoretical ratio.The relative difference between the two ratio values above is just 9.2%.Therefore,this study gives the uncertainty value of the Wahr?s approximate relation between 9.2%-15.0%,which can be used to evaluate the effects on the results of the sepa-rated GIA and present-day mass balance signals.
Keywords：glacial isostatic adj ustmentgravityradial displacementapproximate relationuncertainty
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 905-914 )