Abstract: In this paper, by taking four M_S≥7.8 earthquakes in China continent since the 1960s as research object, namely the 1970 Tonghai M_S7.8 earthquake of Yunnan, the 1976 Tangshan M_S7.8 earthquake of Hebei, the 2001 Kunlunshan Pass M_S8.1 earthquake of Qinghai and the 2008 Wenchuan M_S8.0 earthquake of Sichuan, we investigated the aftershock activity and its classification of great earthquakes around M_S8.0, the physico-mechanical causes of the differentiated features among the types of aftershock sequences are also discussed based on the rheology model. Some preliminary conclusions are drawn: ① the types of aftershock sequences of the four large earthquakes can be divided into two categories, i.e. low activity sequence type and high activity sequence type; ② the differentiated features of aftershock sequences are closely related to the process of the main shock preparation, the theoretical model and actual earthquake data both demonstrate that there is a positive correlation between the duration of aftershock activity and that of great shock preparation; ③ in terms of the research on Wenchuan M_S8.0 earthquake, the rheological property of media in seismogenic zone and the high or low velocity of tectonic deformation may be the important causes of the differentiated features among aftershock sequences of large earthquakes.

Key words: Aftershock sequence, Earthquake mechanism, China Continent