曾宪伟, 谢祖军, 莘海亮. 2014: 2012年11月20日宁夏永宁MS4.6 地震震源机制解与发震构造. 地震学报, 36(5): 790-799. DOI: 10.3969/j.issn.0253-3782.2014.05.004
引用本文: 曾宪伟, 谢祖军, 莘海亮. 2014: 2012年11月20日宁夏永宁MS4.6 地震震源机制解与发震构造. 地震学报, 36(5): 790-799. DOI: 10.3969/j.issn.0253-3782.2014.05.004
Zeng Xianwe, Xie Zujun, Xin Hailiang. 2014: Focal mechanism and seismogenic structure of the Yongning MS4.6 earthquake on 20 November 2012. Acta Seismologica Sinica, 36(5): 790-799. DOI: 10.3969/j.issn.0253-3782.2014.05.004
Citation: Zeng Xianwe, Xie Zujun, Xin Hailiang. 2014: Focal mechanism and seismogenic structure of the Yongning MS4.6 earthquake on 20 November 2012. Acta Seismologica Sinica, 36(5): 790-799. DOI: 10.3969/j.issn.0253-3782.2014.05.004

2012年11月20日宁夏永宁MS4.6 地震震源机制解与发震构造

Focal mechanism and seismogenic structure of the Yongning MS4.6 earthquake on 20 November 2012

  • 摘要: 2012年11月20日在宁夏银川市永宁县与兴庆区交界处发生MS4.6地震,为了更好地了解此次地震的发震构造,首先采用Hypo2000绝对定位方法得到该地震的震中位置及余震分布;然后采用CAP方法反演了此次地震的震源机制解和震源深度. 反演结果表明,永宁MS4.6地震是一个带有少量逆冲分量的右旋走滑地震.该地震矩震级为MW4.3,最佳双力偶解为:节面Ⅰ走向11°,倾角74°,滑动角171°;节面Ⅱ走向103°,倾角81°,滑动角16°.最佳震源深度为8km左右.从该地震震中和震源机制解以及震源深度剖面分布来看,这次地震很可能发生在银川隐伏主断层西侧的次级断层上.

     

    Abstract: The Yongning MS4.6 earthquake on November 20, 2012 is relocated by using the absolute positioning method (Hypo2000), and distribution of aftershocks is also given. In order to investigate the seismogenic structure of the earthquake, focal mechanism and depth of the earthquake are inverted by using CAP method. The inversion result shows that the Yongning earthquake is of dextral strike-slip faulting with a small amount of thrust component, and the moment magnitude is MW4.3. The best double couple solution is 11°/74°/171° for the nodal plane Ⅰ,and 103°/81°/16° for the nodal plane Ⅱ. The estimated focal depth is about 8 km. The earthquake epicenter, focal mechanism solution and cross sections along the focal depth suggest that the earthquake is likely to occur on the secondary fault in the western Yinchuan buried fault zone.

     

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