Polar motion of a triaxial earth and dynamic plate tectonics

Abstract

A theoretical and quantitative analysis of the earth's polar motion, the Chandler wobble and the polar wandering was made under a triaxial, quasi-rigid and rotationally imbalanced earth model and the assumption that the polar excitation was due to the episodic energy perturbation in the earth's upper layers. The Chandler wobble was found to have two frequency components and was quasi-permanent; whereas the polar wandering linked dynamically with the secular tectonic movements in the earth's upper layers. The attempt of the earth to damp its products of inertia for rotation stability maintained the polar motion, while the polar wandering would produce a system of Coriolis torques that provided driving mechanisms to the continental drift, sea-floor spreading and related phenomena, as well as inducing viscous flows in the interior. The secondary deformation due to the earth's non-rigidity was not analyzed in the paper, but the probable connections between the dynamics of polar wandering and the thermal convection in the interior were briefly discussed. The analysis presents the attempt for an integral interpretation of the earth's dynamic evolution or an interpretation of the polar motion, plate tectonics, and the earth's generation and dissipation of excess energy under a unified dynamic theory.