According to provisions of the theory of earth's plates accepted now, all layer of a lithosphere is divided by the deep breaks representing active narrow zones. The ability of movement of separate blocks relatively each other in plastic layers of the top cloak with an approximate speed of 2-3 centimeters a year is result of similar division. These blocks are called earth's plates.
Earth's plates have high rigidity and are capable to keep for an appreciable length of time without changes the building and a form in the absence of influences from outside.
Movement of plates
Earth's plates are in the constant movement. This movement happening in the top layers of an asthenosphere is caused by presence of attendees in a cloak of convective currents. Single earth's plates approach, disperse and slide relatively each other. At rapprochement of plates there are zones of compression and the subsequent nadviganiye (abduction) of one of plates on next, or submoving (subduktion) of nearby formations. At a divergence there are stretching zones with the characteristic cracks arising along borders. When sliding, breaks in which plane the sliding of nearby plates is observed are formed.
Results of the movement
In areas of a convergence of huge continental plates, at their collision, there is massif. In this way, at the time there were mountain Himalayas system formed on border of the Indo-Australian and Eurasian plates. Collisions of oceanic earth's plates with continental formations are result island arches and deep-water hollows. In axial zones of median and oceanic ridges there are rifts (from English Rift – a break, a crack, a crevice) characteristic structure. The similar formation of linear tectonic structure of earth crust having extent hundreds and thousands of kilometers with a width of dozens or one hundred kilometers, results from horizontal stretchings of earth crust. It is accepted to call rifts of very large sizes rift systems, belts or zones. In a type of the fact that each earth's plate is a uniform plate in its breaks the increased seismic activity and volcanism is observed. These sources are located within enough narrow zones in which plane there are friction and mutual movements of the next plates. These zones are called seismic belts. Deep-water trenches, median and oceanic ridges and reeves represent mobile areas of earth crust, they are located on borders of separate earth's plates. This circumstance confirms once again that the course of process of formation of earth crust in these places and proceeds now rather intensively. Importance of the theory of earth's plates cannot be denied. As she is capable to explain existence in some areas of Earth of mountains, in others – plains. The theory of earth's plates allows to explain and provide emergence of the catastrophic phenomena capable to arise around their borders.