Tibetan Plateau And Movement With The Current Tectonic Stress Field Studies And Numerical Simulation,

Tibetan Plateau is one of the regions where the tectonic movement is most acutein the world. Its' special tectonic and geophysical environment make it an idealcontinental geodynamics laboratory. It has always been the focuses of geophysiciststhat the pattern of velocity and deformation, the stress and strain field, and so on. Thispaper has analyzed the nearest ten years GPS observation data of Tibetan Plateau, andapplied the method of adding earthquake central moment tensors to research the stressand strain character of active plots in Tibetan Plateau. Based on these, we haveapplied the theory of solid and fluid mechanics to research the thin shell finite elementmethod and built the synthetic model to compare application effectiveness. At last, wehave applied the thin shell finite element method to simulate 2.5D stable movementpattern of Tibetan Plateau and its neighborhood under the constraint of GPSobservations as well as 2.5D dynamic character of current Tibetan Plateau stress andstrain field distribution based on the assumption of Indo-Asian collision.First, from the comparison and analysis of Tibetan Plateau locomotion anddynamics numerical simulation, we have conclude that there are few research aboutfaults' affection to continental deformation, and most models are 2D which are hard toreflect plateau movement and deformation from both vertical and horizontal sides.Second, through the GPS survey results observation, we have showed that in TibetanPlateau active tectonic blocks, each tectonic block has almost the same movementdirection which is dextral-rotating from south to north step by step. Third, we havecomputed mean tectonic stress stage of each tectonic block by the nearest eighty yearsfocal mechanism solutions of Tibetan Plateau. Derived from scale seismic moment,the stress distributing of each second-order active plots in Tibetan Plateau shows thatthe interior of Tibetan Plateau is wholly compressive and the direct stress axis is NEdirection.At last, on the ground of the tests of the thin shell finite element method and thesynthetic model, we have founded 2.5D finite element model of Tibetan Plateau activetectonic blocks which includes active blocks and main active faults. Using the nearestten years GPS survey data as boundary conditions, taking into account of researcharea topography, lithospheric structure and the inhomogeneity of material property inlaterally divided blocks, applying seismic results to score model results, we havestudied the relation between their motion pattern and deformation character bynumerical simulation. The results show: 1) the interior presents continue deformationwhen the whole Tibetan Plateau moves;2) the collision between Indian and Eurasianplate is the main driving force for the deformation and stress field of Tibet Plateauwhich governs the motion and transformation progress in Tibet;3) Under the pressureof Indian Plate, nowadays, the deformation of Tibetan Plateau's crust is dominated bynorth-south distributed thickening and shortening.