The GIA modest horizontal velocities can provide an important additional constraint to GIA models. GIA models generally predict a pattern of horizontal divergence away from centres of uplift (James and Lambert, 1993; Peltier, 1998, 2002). Near the margin of the formerly glaciated region, horizontal motions may exhibit more complex patterns related to the details of fore-bulge collapse. Further away from the de-glaciated region, the direction of horizontal flow can be directed either toward or away from the loads, depending on the assumed early glacial history and mantle viscosity profile (Mazzotti, 2005). Although the vertical motions are generally consistent with predictions of GIA models, the horizontal data illustrate the need and opportunity to improve the models via more accurate descriptions of the ice load and laterally variable mantle viscosity (Sella et al., 2007).
References
James, T. S., and Lambert, A. (1993). A comparison of VLBI data with the Ice 3G Glacial Rebound Model. Geophysical research letters, 20(9), 871-874. American Geophysical Union.
Mazzotti, S. (2005). Rates and uncertainties on seismic moment and deformation in eastern Canada. Journal of Geophysical Research, 110(B9), B09301. American Geophysical Union. doi:10.1029/2004JB003510.
Peltier, W. R. (1998). Postglacial variations in the level of the sea: Implications for climate dynamics and solid-Earth geophysics. Reviews of Geophysics, 36(4), 603. American Geophysical Union. doi:10.1029/98RG02638.
Peltier, W. R. (2002). Global glacial isostatic adjustment: palaeogeodetic and space-geodetic tests of the ICE-4G (VM2) model. Journal of Quaternary Science, 17(5-6), 491-510. Wiley Online Library. doi:10.1002/jqs.713.
Sella, G. F., Stein, S., Dixon, T. H., Craymer, M. R., James, T. S., Mazzotti, S., and Dokka, R. K. (2007). Observation of glacial isostatic adjustment in “stable” North America with GPS. Geophysical Research Letters, 34(2), 2306. AGU AMERICAN GEOPHYSICAL UNION. doi:10.1029/2006GL027081.
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