Mass Density Variations of Landforms, Active Orogeny and Erosion in the Nepal Himalaya Derived from the Earth Gravity Model EIGEN 6C4

Geomorphic processes and events proceeding during the present collisional orogeny between the IndianIndian lithospheric plate and Asian lithospheric platesAsian lithospheric plate reveal itself in various functions of the gravitational potential. We explore gravity imprint of landform patterns and morphogenetic phenomena in the Nepal HimalayaNepal Himalaya-Nepal Himalayas by means of the global gravity model of the Earth EIGEN 6C4. SelectedEarth groups of gravity aspects are computed from the EIGEN 6C4 through the harmonic potential coefficients over the Himalayan regions. The comparison of geological, geomorphic and gravity data concerning near-surface part of the Earth crust enable the determination of space distribution of a conspicuous evidence of active orogenetic processes, strong erosion of rock assemblages, mass movements and related natural hazards in the Nepal HimalayaNepal Himalaya-Nepal Himalayas. The graphically expressed values of the selected gravity aspects computed from the EIGEN 6C4 show remarkable Himalayan phenomena related to (1) mass distribution of large-scale high mountain landforms, deep-side glacial and fluvial erosion and principal morphotectonic zones recorded by means of second-order derivatives of the gravitational potential; (2) main areas with extensive slope disturbances, giant mass movements and active exfoliation processes determined through virtual deformations of the ellipse of deformation; and (3) variations in the density of rock massifs—detected by arrangements of gravity strike angles—which are caused by their deformations and morphostructural discontinuities created by diverse lithospheric stress fields operating during the collisional orogeny of the Himalaya.