Hypocentral Location and Source Mechanism of the MS7.0 Lushan Earthquake Sequence
详细信息
- 责任者：Lü Jian (Earthquake Administration of Jiangxi Province ; Nanchang 330039 ; China) ; Wang Xiaoshan
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(5)
- 关键词：大震 ; great earthquakes ; 地震序列 ; seismic sequence ; 震源机制 ; focal mechanism ; 四川 ; Sichuan Province
- 页码：p.1753-1763
- 图表：illus., 3 tables, 25 refs.
- 分类号：0500
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
Based on the digital waveforms of China National Seismic Network and Sichuan Seismic Network,The Lushan earthquake sequence(ML≥2.0) was relocated precisely by HypoDD,36 best double-couple focal mechanisms(ML≥4.0) were determined by CAP method.The geometric fault parameters and slip direction were estimated by using distribution of the Lushan earthquake sequence and regional stress field.We analyzed the characteristics of focal depth,focal mechanisms and source rupture to determine the seismogenic structure.The main shock was relocated at 30.30°N,102.97°E;the depth of the initial rupture and centriod is about 15 km and 14 km,respectively;the nodal plane parameters of the best double-couple focal mechanism: strike 209°,dip 46° and slip 94°;strike 23°,dip 44° and slip 86°,respectively.The focal mechanism of main shock is pure thrust type,and most of the focal mechanisms of the aftershocks show the same rupture property as the main shock.The aftershocks(ML≥2.0) distributed in two sides of the main shock,the length of sequence is about 30 km,the focal depth is centrally distributed in 5~27 km;the focal depth of the aftershocks(ML≥3.5) is centrally distributed in 9~25 km and show the focal fault dip toward northwest.We determined the focal fault parameter: strike 207°,dip 50° and slip 92° using distribution of sequences and regional stress field,most aftershocks distributed in the 10 km vicinity of the focal plane.Combine the distribution of earthquake sequence,the focal depth of the main shock with the result of rupture process,we infer that the main rupture extend along the two sides of the fault from the initial rupture point,the southern rupture is a little longer than the northern part,the slip focus on the vicinity of the initial rupture point and the rupture is not up to the surface.Based on the results of this paper,the distribution of seismic intensity and field investigation,we speculate preliminarily the focal fault is the front fault of Longmenshan,but we do not rule out the possibility that there is an unknown base fault nearby the east of main-shock.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |