Abstract: From analysiing the latitude distribution of M≥7.0 earthquakes since 1900 in the globe, it is found that M≥7.0 earthquakes distribute mainly in the latitude range of 35°S to 65°N. The central point is at about 15°N, rather than at the equator. Earthquakes occurring in the longitude range from 0°W to 180°W distribute mainly in the latitude range of 45°S to 25°N with the central point at about 15°S, those between 90°W and 90°E distribute mainly in the latitude range of 40°S to 40°N with the central point nearly at the equator, and those between 0°E and 180°E distribute mainly in the latitude range of 25°S to 55°N with the central point at about 15°N. Further, it is found that the latitude distribution of strong earthquakes in the world coincide with that of the change of kinetic energy of the earth orientation caused by the tide, suggesting that occurrence of strong earthquakes is related to the kinetic energy of the earth orientation. The interaction (inelastic collision) between plates with different masses in the earth lithosphere will take place due to variation in the velocity of the earth orientation, which could be one of the main causes of earthquakes. The inelastic collision could cause some losses of kinetic energy of the plates. The seismic energy could result from the lost kinetic energy.

Key words: Global strong earthquake, Latitude distribution, Earth orientation, Earth lithosphere, Interaction