Using of the Global Gravity Models for Modelling of Rheologic Inhomogeneities in the Crust and Upper Mantle

Abstract Gravity maps of Bouguer anomalies according to terrestrial and marine observations at a scale 1 000 00 are compared with gravity anomalies in the satellite spherical EGM08_CBA_global_2190_2.5m model for the Sea of Okhotsk and the left-bank East Amur regions. An independent probabilistic-deterministic rheological interpretation of gravity anomalies was performed in two systems of their description. Thus, obtained similar models of spatial distributions of density differentiation (contrast) of the crust and a subcrustal mantle reflect rheological states of geological media. Both models similarly reveal the lowered viscosity zones, which rigid crystal blocks in the lower crust and zones of the lowered viscosity zones corresponding to the regional extensional structures in the crust. It was proved that the global spherical gravity EGM08 model is applicable for the tectonic interpretation of regional Bouguer anomalies at a scale M 1 : 1 000 000.