Abstract: This article studies the aftershock sequence of the Wenchuan M_S8.0 earthquake on May 12, 2008, Sichuan province. It is characterized by abundant aftershock sequence and long duration. The aftershocks distribute along the central Longmenshan fault zone extending NE and form a narrow strip and a wedgy distribution in transverse depth profile, which present characteristics of strong convergence and compressive activities between blocks. The focal mechanism of the aftershocks have thrust oblique-slip or strike slip faulting and present complex local tectonic stress field. The Wenchuan M_S8.0 earthquake sequence was determined to be mainshock-aftershock type, and the main judgment references and analysis results are also given in this article.

Key words: Wenchuan M_S8.0 earthquake, Aftershock distribution, Segmentation feature, Shock type determination