Rupture process of the Wenchuan M8.0 earthquake of Sichuan China: the segmentation feature

摘要: Moment tensor solution, rupture process and characteristics of the great Wenchuan 8.0 earthquake are studied by using 39 long-period P SH waveforms with evenly azimuth coverage stations. Our results reveal that M8.0 event consisted 5 sub-events M w⩾7.3 occurring succesively in time space. Rupture started a w7.3 introductory strike-slip faulting first 12 s, then within 12–40 two w 7.6, 7.4 occurred 80 km northeast from initial point dominant type thrust moving. From 40 to 62 7.5 right-lateral on sides Beichuan, 120 away point. The whole lasted 105 s unilaterally propagated WS section Yingxiu-Beichuan fault NE direction, resulting 230-km-long surface zone average dislocation is up 4 m. Two asperities identified formed parts. In part named Dujiangyang-Wenchuan, where located, showed reverse maximum slip 8.2 Around Mianzhu, changed strike Beichuan-Qinchuan large area. area this about 10 depth, shallower than part. 6.53 Consequently, there 2 segments larger 6 One Dujiangyan-Wenchuan segment displacement 6.44 m, other Beichuan-Qingchuan This segmentation may have its geological tectonic background.