Time-dependent rotational stability of dynamic planets with elastic lithospheres

N. H. Chan, J. X. Mitrovica, A. Daradich, J. R. Creveling, I. Matsuyama, S. Stanley

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


True polar wander (TPW), a reorientation of the rotation axis relative to the solid body, is driven by mass redistribution on the surface or within the planet and is stabilized by two aspects of the planet's viscoelastic response: the delayed viscous readjustment of the rotational bulge and the elastic stresses in the lithosphere. The latter, following Willemann (1984), is known as remnant bulge stabilization. In the absence of a remnant bulge, the rotation of a terrestrial planet is said to be inherently unstable. Theoretical treatments have been developed to treat the final (equilibrium) state in this case and the time-dependent TPW toward this state, including nonlinear approaches that assume slow changes in the inertia tensor. Moreover, remnant bulge stabilization has been incorporated into both equilibrium and linearized, time-dependent treatments of rotational stability. We extend the work of Ricard et al. (1993) to derive a nonlinear, time-dependent theory of TPW that incorporates stabilization by both the remnant bulge and viscous readjustment of the rotational bulge. We illustrate the theory using idealized surface loading scenarios applied to models of both Earth and Mars. We demonstrate that the inclusion of remnant bulge stabilization reduces both the amplitude and timescale of TPW relative to calculations in which this stabilization is omitted. Furthermore, given current estimates of mantle viscosity for both planets, our calculations indicate that departures from the equilibrium orientation of the rotation axis in response to forcings with timescale of 1 Myr or greater are significant for Earth but negligible for Mars. Key Points We extend a non-linear, time-dependent theory of true polar wander (TPW) Our extended theory includes stabilization by the so-called ″remnant bulge″ We illustrate the extended theory using models of TPW on both Earth and Mars

Original languageEnglish (US)
Pages (from-to)169-188
Number of pages20
JournalJournal of Geophysical Research: Planets
Issue number1
StatePublished - Jan 2014


  • Earth
  • Liouville equation
  • Mars
  • rotational stability
  • terrestrial planets
  • true polar wander

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science


Dive into the research topics of 'Time-dependent rotational stability of dynamic planets with elastic lithospheres'. Together they form a unique fingerprint.

Cite this