Author(s): W. D. Hibler; E. M. Schulson; R. Kwok
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Abstract: Numerical simulations with initial random weaknesses have successfully simulated oriented linear kinematic features. With coulombic plastic rheologies such simulations tend to yield more prominent faulting features than those with smoothly varying yield curves with a normal flow rule (Hutchings et. al., 2005). Less well appreciated is the dependence of the simulated intersecting angles of such features on the flow rule and degree of dilatation in fixed flow coulombic failure criteria. To rectify this situation a general derivation of the equations of motion for a system undergoing plastic flow and forming linear kinematic features is presented which demonstrates that optimal intersecting faults coincide with the mathematical characteristics of plastic flow in such faults. These characteristics depend on the flow rule as well as the friction angle of the coulombic failure criterion, a result which is verified numerically using numerical simulations with heterogeneous strengths and fixed wind forcing together with weakening or strengthening. Also presented is a scaling relation for spacing of linear kinematic features depending on wind stress gradient, average ice strength, and the distribution of weaknesses in the ice pack.
Year: 2008