Anomalous internal structure of the terrestrial planets from gravitational field and topography: first results of the exploration of Marsтезисы доклада
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
Аннотация:In this paper we apply a new technique that we have developed earlier [1,2] for solving incorrect problem of determining the internal structure of the planets based on space research of the gravitational field and relief. The essence of this method is the determination of possible depths of compensation for expansion harmonics of topographic heights relative to the equilibrium ellipsoid for different-order and different-degree harmonics. The solution of this problem should satisfy a system of two equations. The first equation represents the consistency between the contribution of topographic and compensating masses to the gravity and the observations. The second equation represents the fact that the pressures below the compensation depth are equal to the pressures of the equilibrium model. Since each topographic heterogeneity is characterized by a certain set of the harmonics therefore the maximal concentration of compensation of this set within a certain limited depth interval may indicate the most probable depths of compensation of the considered topographic heterogeneity .
The paper also carried out a comparative analysis of the internal structure of the Earth and Mars, in order to identify the reasons for the differences in their geophysical and geodynamic features, such as: the distribution and level of isostatically unaligned stresses, the nature of convective motions caused by anomalies in the internal gravitational field, the existence of the magnetic field on the Earth and the lack of the magnetic field in Mars. To do this, on the basis of the analysis of the distribution histograms for the depths of compensation determined the most likely levels of compensation of topographic irregularities. On the selected depths , we constructed the maps of lateral distributions of the compensating masses. It is shown that the observed anomalous structures generate the anomalies in the internal gravity field, which may be the cause of convective motion in the mantle and core of the planet [3].
REFERENCES
1. Chuikova N.A., Nasonova L.P. , and Maksimova T.G. Anomalous structure of the Crust and Mantle of Mars. ISSN 0027-1349, Moscow University Physics Bulletin, 2011, Vol.66, No. 1, pp. 64-71
2. Chuikova N.A., Nasonova L.P. , and Maksimova T.G. Anomalies of Density, Stresses, and the Gravitational Field in the Interior of Mars. ISSN 0027-1349, Moscow University Physics Bulletin, 2012, Vol.67, No. 2, pp. 218-225
3. Chuikova N.A., Nasonova L.P. , and Maksimova T.G Density, Stress, and Gravity Anomalies in the Interiors of the Earth and Mars and the Probable Geodynamical Implications: Comparative Analysis. ISSN 1069_3513, Izvestiya, Physics of the Solid Earth, 2014, Vol. 50, No. 3, pp. 427–443.