<p>High accuracy repeated gravity observations within Vrancea active seismic zone, where upper mantle seismicity occurs within full intra-continental environment and no evidence on an active subduction, have succeeded to outline the overall lowering of the gravity over the epicentres area, unexpectedly associated with a local relative subsidence of topography, superposed on the overall trend of Carpathians uplift following denudation and erosion of the mountains catena. A particular gravity decrease related to seismicity was also unveiled by successive gravity campaigns conducted prior and after some significant earthquakes (M 5+). As the vertical deformation of the crust may not explain the gravity change in the area, attempts have been made to model and understand genesis of the mass deficit responsible for the observed gravity. Solutions provided by gravity inversion and some 2D and 3D forward modelling have been interpreted in terms of vertical stretching of the upper part of the crust under the gravity pull generated by eclogitization of the lower crust penetrating the upper mantle. Given the subduction-related scenarios, often used to explain the Vrancea seismicity, may not offer the mechanical environment to justify the lithosphere stretching, some alternative, non-conventional geodynamic models like Rayleigh–Taylor gravitational instability, or the unstable triple-junction are suggested to explain the phenomenon.</p>