宁夏石嘴山震群的微震匹配定位及其发震构造

发布时间：2018-05-17 19:51

  本文选题：匹配定位 + 双差定位　； 参考：《地震地质》2017年04期

【摘要】：采用新发展的匹配定位(ML)方法检测与定位2014年2月28日宁夏石嘴山M_L4.4震群地震目录中遗漏的微小地震事件,共检测定位34次地震,是宁夏台网定位地震数目(13次)的近3倍;地震数明显增多,地震目录完整性明显改善,为更科学合理地研究震群活动过程和发震构造提供了可能。利用CAP方法反演得到的主震最佳双力偶解为节面Ⅰ:走向354°,倾角70°,滑动角166°;节面Ⅱ:走向89°,倾角77°,滑动角21°;矩震级为M_W3.9;震源以走滑错动为主带有少量逆冲分量。结合主震双差定位结果和震源机制最佳拟合深度,认为主震深度为7~8km,属于浅源地震。结合银川盆地深地震三维成像研究成果,认为主震及最大余震发生于上地壳内的可能性较大,其余地震则主要发生于沉积层底部或者是上地壳结晶基底的顶部。震群活动时空演化图像显示,震群整体分布呈现近SN向展布,余震主要集中于主震以北区域,并呈现较明显的由南向北逐步延伸的态势,随着余震向北发展震源由深部向浅部迁移。地震深度剖面投影图像及主震震源机制解结果均显示发震断层E倾,倾角较大,表明石嘴山震群发生于贺兰山东麓断裂的可能性较大。地震地表投影图像显示震中分布延展至贺兰山东麓断裂北端终止点以北,由此推测贺兰山东麓断裂存在继续向北延伸的可能。
[Abstract]:In this paper, the newly developed matching locator (MLL) method is used to detect and locate the minor earthquake events missing from the M_L4.4 earthquake catalogue of Shizuishan, Ningxia on February 28, 2014. A total of 34 earthquakes are detected and located, which is nearly 3 times as many as 13 earthquakes located in Ningxia network. The number of earthquakes increases obviously and the integrity of earthquake catalogue is improved obviously, which provides the possibility for more scientific and reasonable study on the process of earthquake swarm activity and seismogenic structure. The optimum double couple solutions of the main shock obtained by CAP method are as follows: strike I: strike 354 掳, inclination 70 掳, slip angle 166 掳; Nodal 鈪，

本文编号：1902635