地震工程学报2017，Vol.39Issue(1)：112-118,7.DOI:10.3969/j.issn.1000-0844.2017.01.0112
2010年玉树地震序列M L≥4.0事件 震源机制解特征分析
Focal Mechanism Solution Analysis of M L≥4.0 Earthquakes in the 2010 Yushu Earthquake Sequence
摘要
Abstract
In this study,we inverse 19 focal mechanism solutions of the foreshock,mainshock and aftershock events in the M S 7.1 Yushu earthquake sequence by the method of CAP.The results show that the 19 focal mechanism solutions are mainly strike-slip types,and the fore shock is similar to the main shock which reflects that the intimate relationship between the two events. The focal depth concentrates on about 7~12 km,and two aftershocks with the most shallow (4.5km)and deepest (34 km)facal depth significant thrusting and exhibited obviously boundary fea-ture.The Epicenters of 19 events distrbute in the Yushu-Longbao fracture which is the northern branch of Ganzi-Yushu fault and it has been proven that the Yushu-Longbao fracture is the seismogenic structure of Yushu earthquake.Following the SE-NW direction along Yushu-Long-bao fault pull a cross-section to observe the change of focal depth along the profile ,we can see that the focal depth of Northwest section of Yushu-Longbao fault is greater than the southeast section,and this part is the main part in the late aftershock activity,so that the aftershocks have extended deep crust in the late seismic activity and the fracture-accumulated strain can be further released.The dominant distribution of P axis azimuth is 220°~230°while T axis azimuth is 310°~320°,and the two distributions are vertical to each other.It is found that the regional stress field is relatively uniform by analyzing the data of the focal mechanism solutions of historical earth-quakes and GPS,which shows that the M S 7.1 Yushu earthquake is the normal release of the en-ergy in the Earth.关键词
玉树地震/震源深度/CAP方法/震源机制解Key words
Yushu earthquake/focal depth/CAP method/focal mechanism solutions分类
天文与地球科学引用本文复制引用
石学录,姚家骏,张博..2010年玉树地震序列M L≥4.0事件 震源机制解特征分析[J].地震工程学报,2017,39(1):112-118,7.基金项目
中国地震局兰州地震研究所地震科技发展基金(2012Y04) （2012Y04）
国家自然科学基金项目(41304048) （41304048）
