Sidorenkov - Head, Laboratory of planetary circulation, Hydrometcentr of Russia, Bolshoi Predtechenskii per. ۱۱-۱۳, Moscow, ۱۲۳۴۵۸, Russia

The non-tidal irregularities of the Earth rotation are mainly due to the exchange between the angular momentum of the solid lithosphere and its fluid environment - the atmosphere and the hydrosphere. This exchange occurs at the expense of the moments of the frictional forces and pressure forces pushing on mountain ranges. The moment of forces effecting on an individual plate, determines the vector of the movement of the plate. The estimations of the orders of magnitudes of the atmospheric and oceanic forces effecting on a separate plate and of the stresses of the interaction between plates are given. Under the effect of the atmospheric and oceanic forces the plates interacts with the circumjacent plates through the frontal contacts. The stresses may reach such high values (106-107 N/m2), at which the discontinuity and displacement of plates from each other occur, and triggers the earthquakes. The mechanical action of the atmosphere and ocean on the lithosphere plates defines relative movement between the plates and can be cause of the earthquakes and volcanic. The empirical facts, which evidence for the benefit of this conclusion, are given. It is necessary to carries out the monitoring of the atmospheric and oceanic forces separately for every lithosphere plate. The time series of these forces make it possible forecasting of a seismic activity.