Gravity anomalies in the Earth's crust and upper mantle

Depths of the Relief Compensation and the Anomalous Structure of Crust and Mantle of Mars

“…an order of size 0.013 in comparison with mean planetary radius R = 3389.5 km. For the Earth where the maximum range of variations of the relief heights led to uniform density, is an order 0.002 R, it has been shown by us [2], that considerable anomalies of an internal gravitaty field and a field of crust's stresses can support existing differences of heights, despite of denudation's processes. Such considerable gravity anomalous in a crust arise that basically the depth distribution of anomalous masses has a dipolar pattern owing to process of isostatic compensation.…”

“…This problem was solved in the linear approximation. However, our similar studies of density structure of the Earth' crust showed that the linear approximation is insufficient for the accurate accounting of the contribution of the crust boundaries in the internal and external gravitaty fields, it is necessary to take into account the quadratic members [2,7,8]. Thus, the account of quadratic members from the relief' expansion of the degree N brings the additional contribution to harmonics of potential of degree n=0-2N, with this contribution increasing with the growth of n. Especially the account the quadratic terms is essential in dipole (by depth) distribution of anomalous masses.…”

“…In the linear approximation the laterally distributed anomalous masses are represented as a simple layer of continuous density distributed on a sphere. In this case, there is a linear relation between the coefficients of the expansion of a simple layer density in terms of spherical harmonics and the Stokes constants caused by the the layer's contribution [2]:…”

Anomalies of density, stresses, and the gravitational field in the interior of mars

“…Since seismic studies have not been carried out on Mars, preliminary information about its internal composition can be obtained using the observational data on its gravitational field and relief, as well as some theoretical conclusions verified when studying the density structure of the Earth. Earlier, we developed the technique for determining (in quadratic approximation) the contribution of anomalous masses distributed over ellipsoidal surfaces to a planet's gravitational field [1]- [3] and applied this technique when studying the structure of the envelopes of Earth and Mars [4,5]. In this paper, we estimate the possible distributions of relief compensation depths and anomalies of density and stresses more accurately, as well as anomalous gravitational field in the crust, mantle, and core of Mars.…”