Deformations of the Earth's mantle due to core displacements
Source: Astronomical and Astrophysical Transactions, Volume 24, Number 3, Number 3/June 2005 , pp. 195-213(19)
Publisher: Taylor and Francis Ltd
Abstract:The planet is assumed to consist of an absolutely rigid sphere to which the viscous elastic spherical shell (the mantle) is connected from the external side. In the undeformed state the centres of mass of the mantle and the core coincide and the shells have concentric positions. The centre of mass of the core is considered to be displaced according to a definite law relative to the centre of mass of the mantle in its undeformed state among to the differential action from external celestial bodies. The solution of the problem of elasticity is obtained using a restricted treatment by taking into account only the mutual interaction of the mantle and the moving core and by neglecting the non-sphericities of the core and the mantle. The corresponding effects of the mantle deformations caused by the external bodies are known and can be studied separately on the basis of the principle of superposition. The deformations of the Earth's mantle due to secular drift of the core along the polar axis are described. The phenomenon of the contrasting tendencies in the deformations northern and southern hemispheres of the Earth (expansion and contraction, respectively) is discovered. The evaluation of the velocity of the core drift relative to the mantle's centre of mass has been obtained and was found to be equal to 8.0 cm year -1 .
Document Type: Research Article
Publication date: June 1, 2005