Irregularity of lithospheric stress as a result of plates structure

Research of stress distribution in earth crust is one of actual problems of geophysics and geoinformatics. It is important for understanding of mechanisms of tectonic movements of Earth's plates and seismic manifestations of the release of such stresses in the form of earthquakes. In projects such as “World stress map”, maps are built, showing the orientation of maximum horizontal compressional stress. These ones are concentrated mainly in the collisions of oceanic and continental plates and have a very uneven distribution in amplitudes and directions. In view of traditional plate tectonics based on theory of continuous medium for the description of lithosphere deformation it is difficult to explain these irregularities. We suggest to give such explanations on the basis of views of the lithosphere as the structured environment. According to the modern concepts such structured plates can be described by a set of interacting blocks which compression causes localization of tension along chains of consistently located blocks in the direction of compression. Maximum tension in places of collision will be concentrated in the certain places (created by chains of tension in oceanic plate) . We modelled such scenarios of the collision in experiment with use of the photoelastic analysis and in numerical modeling by the finite-element method. Results qualitatively match and it confirms the hypothesis of specific interaction of plates of Earth's crust as block structured medium.