2013年12月16日巴东M5.1地震序列及发震构造分析
发布时间:2017-12-27 23:31
本文关键词:2013年12月16日巴东M5.1地震序列及发震构造分析 出处:《地震地质》2016年03期 论文类型:期刊论文
更多相关文章: 双差定位 震源深度剖面 震源机制 构造应力场 ETAS模型
【摘要】:2013年12月16日湖北省巴东县发生M5.1地震,该地震是三峡库首区自2003年蓄水以来震级最大的1次。双差地震精定位结果显示,巴东地震序列呈NEE向线性展布,主震震源较深,余震震源深度逐渐变浅。垂直余震优势展布的震源深度剖面均显示出向SE变深的特征;倾角约50°左右,向深部变缓,揭示可能的发震断层走向NEE,倾向SE,倾角约为50°。利用矩张量反演得到了主震的震源机制解,与地震序列定位分析比较吻合的是NEE向节面,综合判断该节面可能为发震断层,倾向SE,倾角50°左右,性质以走滑为主兼逆冲分量。利用P波初动方法求解了ML2.0以上余震的震源机制,并采用FMSI程序反演得到了震源区的构造应力场,结果显示其方向与区域现代构造应力场方向一致,说明该地震序列受区域应力场的控制。地震序列发生在175m高水位运行期的水位缓慢降落阶段,基于ETAS模型对流体触发作用进行了定量检测,显示库水对地震序列的触发作用占17%,余震自激发占83%。综合分析认为,巴东M5.1地震为库水触发的构造型地震,NEE向断裂构造为可能的发震构造。
[Abstract]:In December 16, 2013, the M5.1 earthquake occurred in Badong County, Hubei Province, which was the 1 largest magnitude since the storage of the Three Gorges Reservoir since 2003. The results of the double difference seismic precision show that the Badong earthquake sequence is NEE linear, the main earthquake source is deeper and the focal depth of the aftershock is gradually shallower. The vertical depth profiles of the vertical aftershocks show the characteristics of SE depth. The dip angle is about 50 degrees, and the depth changes slowly, revealing the possible trend of NEE, SE, and the dip angle is about 50 degrees. The focal mechanism solution of main shock is obtained by using moment tensor inversion. It coincides with the NEE section to locate the earthquake sequence. It is judged that the joint surface may be a seismogenic fault. It tends to SE, and the inclination is about 50 degrees. The main character is strike slip and thrust component. The focal mechanism of aftershocks over ML2.0 has been solved by P wave initial motion method. The tectonic stress field in the focal area has been retrieved by FMSI program. The results show that the direction is consistent with the direction of modern tectonic stress field in the area, indicating that the earthquake sequence is controlled by the regional stress field. The earthquake sequence occurred at the stage of slow fall of 175m high water level operation period. Based on the ETAS model, we quantitatively detected the fluid triggering effect. It showed that the triggering effect of reservoir water on the earthquake sequence accounted for 17%, and the aftershock self excitation accounted for 83%. The comprehensive analysis shows that the Badong M5.1 earthquake is a tectonic earthquake triggered by the reservoir water, and the NEE fault structure is a possible seismogenic structure.
【作者单位】: 中国地震局地球物理研究所;中国地震局地震研究所地震与大地测量重点实验室;
【基金】:国家自然科学基金(41304046) 中国地震局社会公益研究项目(1521401800043)共同资助
【分类号】:P315.2
【正文快照】: 2)中国地震局地震研究所,地震与大地测量重点实验室,武汉4300710引言2013年12月16日13时4分,湖北省恩施土家族自治州巴东县发生M5.1地震,此次地震距离三峡水库大坝约66km,震中烈度达Ⅶ度,是三峡水库2003年5月蓄水以来发生在库首区的最大地震。此次地震共造成5人受伤,约740人失,
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