Abstract
We probe the gravitational properties of two neighboring planets, Earth and Venus. To justify a comparison between gravity models of the two planets, spherical harmonic series were considered up to a degree and order of 100.
The topography and gravity aspects, including l(zz) (vertical derivative of the vertical component of the gravity field), strike alignment (SA), comb factor (CF), and l(2) invariant derived from the Marussi tensor, were calculated for the two planets at specifically selected zones that provided sufficient resolution. From G(zz) we discovered that the N-NW edge of Lakshmi Planum does not show any subduction-like features.
Its G(zz) signature resembles passive continental margins on Earth, like those surrounding the Indian Peninsula. Moreover, according to SA and CF, the Pacific and Philippine-North American Contact Zone on Earth indicates significantly higher level of deformation due to convergent motion of the plates, whereas the deformation level on Venus is significantly smaller and local, when considering an equatorial rifting zone (ERZ) of Venus (between Atla-Beta Regios) as diverging boundaries.
The strain mode on the East African Rift system is smaller in comparison with ERZ as its Venusian analog. The topography -I-2 analysis suggests a complicated nature of the topographic rise on Beta Regio.
We show that specific regions in this volcanic rise are in incipient stages of upward motion, with denser mantle material approaching the surface and thinning the crust, whereas some risen districts show molten and less dense underlying crustal materials. Other elevated districts appear to be due to mantle plumes and local volcanic activities with large density of underlying material.