HR: 16:00h
AN: NG12C-01    [PDF]
TI: A Damage Mechanics Model for the Continuum Rheology of the Upper Continental Crust
AU: * Glasscoe, M T
EM: glasscoe@geology.ucdavis.edu
AF: Department of Geology, University of California, Davis 1 Shields Avenue, Davis, CA 95616 United States
AU: Turcotte, D L
EM: turcotte@geology.ucdavis.edu
AF: Department of Geology, University of California, Davis 1 Shields Avenue, Davis, CA 95616 United States
AB: Deformation of the lithosphere is clearly complex. Ideally, the lithospheric plates are rigid and displacements are restricted to plate-boundary faults. But it is clear that broad zones of deformation occur within the lithosphere, particularly the continental lithosphere. Although this deformation may be primarily restricted to faults in the upper continental crust, it may still be appropriate to treat this deformation using a continuum approach. A standard engineering approach to brittle deformation of a solid is to use damage mechanics. There is also a close association between damage mechanics and the behavior of fiber bundles. We derive a continuum model for deformation assuming that broken fibers in a fiber bundle are instantaneously replaced by new, unstressed fibers. The result of our analysis is a non-Newtonian viscous rheology. We show that the same result can be obtained using damage mechanics directly. Using Omori's law for the decay of aftershocks, we conclude that the power-law exponent in the non-Newtonian rheology is in the range 5 to 15. With this strong nonlinear viscous rheology, the behavior of the deforming upper crust approaches that of a perfectly plastic material.
DE: 3200 MATHEMATICAL GEOPHYSICS (New field)
DE: 3210 Modeling
DE: 3220 Nonlinear dynamics
DE: 3230 Numerical solutions
DE: 3250 Fractals and multifractals
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting