Influence of Internal Load on the Non-Hydrostatic form of the Moon

Abstract

The viscoelastic deformations of a graviting rotating multilayered Maxwell planet, submitted to a volumic external potential and to internal loads, are computed using a Love number formalism. First, for such a body, we calculate the relaxation modes associated with the viscoelastic Love numbers: they are due to various discontinuities in density, in rigidity or in viscosity at each interface of the multilayered planet. If an internal load is located at an interface “i”, the relaxation mode due to the density jump at this interface “i” will be excited. For the Moon, such a mode creates viscoelastic deformations (in the radial displacement and in the mass redistribution potential) at the surface which relaxes with a relaxation time of about some billions years, that is, at time scale of the Moon age, quasi-constant deformations.