HR: 0800h
AN: T11B-1260    [Abstracts]
TI: Insight Into 3-D Earth Structure From a New Generation of Glacial Isostatic Adjustment Models
AU: * Latychev, K
EM: latychev@physics.utoronto.ca
AF: Dept. of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7 Canada
AU: Mitrovica, J X
EM: jxm@physics.utoronto.ca
AF: Dept. of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7 Canada
AU: Tamisiea, M E
EM: mtamisie@cfa.harvard.edu
AF: Harvard Smithsonial Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Tromp, J
EM: jtromp@gps.caltech.edu
AF: Seismological Laboratory, California Institute of Technology, Mail Code 252-21, Pasadena, CA 91125 United States
AU: Moucha, R
EM: moucha@physics.utoronto.ca
AF: Dept. of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7 Canada
AB: Predictions of glacial isostatic adjustment (henceforth GIA), and analyses of related geophysical observables, have generally been based on normal mode approaches valid for spherically symmetric Earth models. We explore the impact of lateral variations in elastic plate strength, including the presence of plate boundaries and variations across the ocean-continent interface, and mantle viscosity, on predictions of 3-D crustal velocities and long-wavelength gravity anomalies. Our calculations adopt a realistic, global model of Late Pleistocene deglaciation and meltwater redistribution and they are based on a new, finite-volume formulation of the (Maxwell) viscoelastic GIA problem. We find that the introduction of realistic mantle and lithosphere structure perturbs GIA-induced crustal velocities at levels which can significantly exceed the current observational uncertainties of space-geodetic methods (e.g., GPS). Predictions of secular variations in long-wavelength harmonics of the geopotential are, in contrast, primarily sensitive to deep mantle viscosity structure. We compare the sensitivities evident in our suite of forward models with global and site-specific geodetic data to assess the prospects for using GIA observations to constrain 3-D Earth structure.
DE: 8160 Rheology--general
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 1234 Regional and global gravity anomalies and Earth structure
DE: 1236 Rheology of the lithosphere and mantle (8160)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting