31st Annual Meeting of the DPS, October 1999
Session 46. Mars Surface: Evidence of Change Posters
Poster Group II, Thursday-Friday, October 14, 1999, , Kursaal Center

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[46.06] Mars: Viscoelastic Reponse and Planetary Rotational Dynamics

O. Aharonson, B.H. Hager (MIT)

There are several reasons to believe that Mars may have undergone True Polar Wander (TPW) including the equatorial position of the large gravity anomaly associated with Tharsis, the potential for loading and unloading by polar volatile transport, and the evidence for remnant ice deposits away from the present rotational pole. We model here the visco-elastic response and rotational dynamics of a self gravitating, incompressible, spherical Mars with radial density stratification appropriate for a crust, mantle, and core. The Load and Tidal degree 2 Love numbers are analytically computed, and from these the rotational response of the planet is recovered.

Mass anomalies with non-zero degree two gravity component placed away from the equator and pole can drive the orientation of the spin axis to change such that a positive (negative) mass anomaly tends towards the equator (pole). Part of the response to the rotational potential (the rotational fossil bulge) is a degree two field that tends to stabilize the planet against reorientation. We investigate here and quantify the possibility for TPW on Mars. Presented are preliminary results on the potential for reorientation as a function of the structure and rheology of the interior.

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