Crustal Displacement can be expressed mathematically as follows:
A sphere of known dimensions, the radius being slightly shorter at the top and bottom of its rotational axis, the average radius being 6,378.1 km, the sphere being made up of a solid inner core, a liquid outer core, the Gutenberg Discontinuity, then, the inner mantle of median depth 2,650 km; above this is the mesosphere; a plastic layer called the athenosphere follows.
The upper mantle merges into continental or sea crust, which will be referred to as a hollow sphere, which, totally surrounds and encompasses the inner sphere. Between the crust and the upper mantle is a layer called the Moho discontinuity. This outer shell or sphere is made up of many interlocking plates which slide, shift, butt and subduct, these are held in situ by gravity and centripetal force. They adhere to the lower sphere by the viscosity of the athenosphere and upper mantle. The outer segmented sphere has a liquid layer of mass that is spread over the surface of the outer shell.
Due to the rotational pattern of the combined spheres around the sun and its obliquity off the ecliptic, this liquid mass collects at the poles periodically, turning solid, then turns liquid once more, having periods of accumulation at the poles approximately 250,000 years and periods of melting leading to mass accumulation around the equator of around 15,000 years. The plates of the outer shell, because of this shift in mass, are affected by torque and angular acceleration. When the liquid mass collates in the equatorial and temperate regions, dissipating from the polar axial regions, the amount of torque or angular acceleration will rise, this will be proportionate to the shift in mass from polar axial regions.
The reverse will be true if mass is shifted to the polar areas. This torque and angular acceleration moves the plates until an exponential rise of force applied to the plates within a very short time period, forces the plates to act as one solid spherical shell. Once the Maximum Friction Tolerance of the adhering layer is reached, the outer shell will break free and gyrate until it reaches a new position of equilibrium. . .
The question would be, knowing the relative densities, volumes and masses, etc: At what point will the outer shell break free? A point to remember here is; the polar areas of the sphere will not have the same Angular Velocity that the Equatorial regions will have, i.e, the region around the equator will experience greater Angular Acceleration because of the increase in mass (Water accumulation from the melting polar regions) it has gained.