【摘要】 2008年5月12日,青藏高原东缘龙门山断裂带发生Mw7.9级汶川地震,该地震使得北川—映秀断裂、灌县—江油断裂带发生了同震破裂。本文主要利用"中国地壳运动观测网络"项目组提供的GPS同震位移资料,采用基于敏感度迭代拟合法(SBIF)及分段发震断层模型,分别应用均匀半空间和分层地壳结构两种方法反演分析该次地震的精细同震滑动分布。结果表明:①SBIF反演方法应用于相对较小的GPS数据集仍然可以获得理想的同震滑动分布;②采用考虑分层地壳结构模型的反演结果整体上要优于均匀半空间模型的结果;③同震滑动主要发生在10～19km深度以上,且存在五个滑动峰值区域及北川断裂南西端存在明显的深部滑动区,与震后野外考察结果及余震分布相吻合,同时能够较好地解释GPS观测数据;④青川断裂存在明显的右旋走滑分量,其平均滑动量为1.99m,北川断裂主要发生逆冲滑动,平均滑动量为3.35m,灌县断裂的平均滑动量为0.65m;⑤反演得到的地震矩为8.74×1020Nm(Mw7.90),与地震学结果吻合。更多还原

【Abstract】 On 2008 May 12,The Mw 7.9 Wenchuan earthquake along the Longmenshan Fault zone,occured at the eastern margin of the Tibetan Plateau,rupturing the Beichuan-Yingxiu and Guanxian-Jiangyou faults.Based on the segmenting fault model,we derive the fine slip distribution by utilizing a sensitivity-based iterative fitting method(SBIF) to GPS datasets mainly from the Crustal Movement Observation Network of China(CMONOC),with the two models of the homogeneous half space and the stratified crustal structure.The results show:①The coseismic slip distribution still can be inversed reasonably by applying a sensitivity-based iterative fitting method to the relatively minor GPS datasets;② The inversion results considering the stratified crustal structure are superior to them from the homogeneous,half space in the mass;③ The coseismic slip is concentrated to above the 10～19 km depth.There exist five slip peak zones and obvious slip distribution at the lower part of SW Beichuan fault,in line with the field investigations and the aftershocks,also can resolve the GPS observations better;④ The Qingchuan fault experienced distinct right-lateral slip,and the magnitude of mean slip is 1.99 m.However,the Beichuan fault mainly experienced thrust slip,and the magnitude of mean slip is 3.35 m.The magnitude of mean slip for Guanxian fault is 0.65 m;⑤ The inversed moment is 8.74×1020Nm(Mw 7.90),consistent with seismic estimates.更多还原