Abstract: Using the global large earthquake catalog of China Earthquake Network, we analyzed the temporal characteristics of great earthquakes (M_S≥8.0) and the spatial distribution of large earthquakes (M_S≥7.8). And the tendency of large earthquakes (M_S≥7.8) in Western China continent and its surroundings was also discussed. It seems that the temporal characteristics of great earthquakes (M_S≥8.0) on the earth has period of a hundred years, and the seismicity is higher in the former 50 years and lower in the latter 50 years and it comes to high in the new century. And there is rhythm activity of 20 years in the hundred years period, reflected mainly in the large earthquake cyclic process of activity and quiescence alternatively in Med-Himalayan seismic zones. Since the new century, large earthquakes in Med-Himalayan seismic zones occurred frequently, showing a high activity trend based on the characteristics of great earthquakes cyclic process of the globe. By calculating the variance-coefficient of different magnitude in Western China continent and its surroundings, we found that seismic process with different magnitude has different activity type. By using the log normal cumulative distribution function fitting the seismic processes with different magnitude, we found that the probabilities of great earthquake (M_S≥7.8) in Western China continent and its surroundings by 2015 will be 0.80 and will be 0.89 by 2015, which means large earthquakes in the triangular region would occur frequently.

Key words: Global Seismicity, Western China continent and its surroundings, Large earthquake cyclic process