3D finite-elements kinematic model of the Adria Northern region: stress analysis

The 3D finite-element method is used in the present work to model the present complex and inhomogeneous stress field on the northern boundary of the so-called Adria microplate (north-eastern Italy). With the aim of providing some possible explanation for the observed stress-strain pattern as a result of plate driving forces, a 3-D linear elastic-static finite-element model of the lithosphere has been constructed, based on geological, seismic and gravimetric evidence. The boundary conditions imposed on the model throughout the experiment depict different scenarios for the kinematics of the region. They are conditions that we try to tune, in order to obtain the best fit with the available observations, i.e. the stress orientations, and the fracturing distribution. In particular, two main kinematic problems are considered: the orientation of the far-field compression acting in the region, and the modalities through which the resulting shortening is achieved. The best fit with the observational data is obtained hypothesizing strike-slip effects at both the eastern and western boundaries. Moreover, as effects of the apparent counterclockwise rotation of the Adria plate, the N-S compression acting at the southern boundary of the model increases with longitude. The results are in agreement with the seismological and deformational observations and with the current hypotheses on the mechanisms that rule continental collision.