Eos Trans. AGU, 85(17), Jt. Assem. Suppl., Abstract G21D-03 INVITED, 2004

The Plausible Range of GIA Contributions to 3-D Motions at GPS Sites in the SNARF Network

Tamisiea, M E
Email: tamisieacolorado.edu
Address: University of Colorado, 440 UCB,
Boulder, CO 80309-0440 United States

Mitrovica, J X
Email: jxmphysics.utoronto.ca
Address: Department of Physics, University of Toronto, 60 St. George St.,
Toronto, ON M5S 1A7 Canada

Davis, J L
Email: jdaviscfa.harvard.edu
Address: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
Cambridge, MA 02138 United States

A significant contribution to the secular crustal deformation across North America is the continued recovery from loading effects caused by the Late Pleistocene ice sheets (glacial isostatic adjustment or GIA). The crustal motions driven by this process are quite large (horizontal motions on the order of 1 mm/yr across the plate and vertical motions of over 1 cm/yr near the loading centers). Unfortunately, both the Late Pleistocene ice history and the viscosity model of the solid Earth remain uncertain. The range of model predictions derived by considering reasonable variations in these inputs can be as large as the signals. In this talk, we first consider reference frame and orientation issues that arise when comparing model predictions to GPS observations. We then examine a suite of model predictions using both ICE-I (a history based on geological data alone) and ICE-3G (constrained, in part, from geophysical data sets) as well as viscosity models that include a range of lithospheric thicknesses and mean upper and lower mantle viscosities. We compare these results at GPS sites that may be included in SNARF to determine if a subset of these stations exhibit consistent or small GIA contributions; this consistency could be used as a site selection criteria for SNARF.

Last modified Thursday, 22-Dec-2005 22:10:01 UTC

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