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地震 ›› 2017, Vol. 37 ›› Issue (3): 95-106.

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2013年芦山地震和2014年鲁甸地震前巧家台阵观测到的地震活动增强现象

李艳娥1, 陈丽娟2, 陈学忠1   

  1. 1.中国地震局地球物理研究所, 北京 100081;
    2.重庆市地震局, 重庆 401147
  • 收稿日期:2016-12-14 发布日期:2019-08-09
  • 作者简介:李艳娥(1983-), 女, 河北沧州人, 副研究员, 主要从事地震预测研究。
  • 基金资助:
    川滇国家地震监测预报试验场运维项目资助

Enhancement of Seismicity Recorded by the Qiaojia Seismic Network before the 2013 Lushan and 2014 Ludian Earthquakes

LI Yan-e1,CHEN Li-juan2,CHEN Xue-zhong1   

  1. 1.Institute of Geophysics, CEA, Beijing 100081, China;
    2.Earthquake Administration of Chongqing, Chongqing 401147, China
  • Received:2016-12-14 Published:2019-08-09

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摘要： 中国地震局地球物理研究所在川滇菱形块体东边界的小江断裂带北段布设了巧家地震观测台阵, 2012年2月底开始运行以来, 在其附近地区先后发生2013年4月20日四川芦山MS7.0地震和2014年8月3日云南鲁甸MS6.5地震。 本文利用2012年3月至2014年7月巧家台阵观测到的地震活动资料, 分析了芦山地震和鲁甸地震前巧家台阵观测区域范围内地震活动的异常特征。 结果显示: ① 巧家台阵记录到的全部地震分布区域内M≥2.0地震频次随时间的变化显示, 地震频次在芦山MS7.0和鲁甸MS6.5地震前都出现了明显的上升变化过程, 且在鲁甸地震前地震频次上升幅度比在芦山地震前明显大, 地震频次上升过程持续时间在鲁甸地震前比在芦山地震前明显长。 ② 在台阵覆盖范围内, 地震频次随时间的变化显示出如下特点: 对于震源深度h≤10 km的地震, 其频次在芦山MS7.0和鲁甸MS6.5地震前都出现了非常明显的上升变化过程, 且上升过程持续时间相同, 约为5个半月; 对于震源深度h>10 km的地震, 其频次在芦山地震前出现上升—下降变化过程。 芦山地震发生之后, 其频次再次出现上升下降过程。 h≤10 km的地震与h>10 km的地震之间, 其频次存在反向变化现象。 ③ 在台阵覆盖范围及邻近区域内, 芦山地震前, 震源深度在10 km上方和下方的地震活动同步出现增强变化过程, 而在鲁甸地震前, 在10 km上方地震活动呈增强变化特征, 而在10 km下方的地震活动呈减弱变化特征。 上述结果显示, 在芦山地震和鲁甸地震前, 巧家台阵及其邻近区域地震活动均出现了显著的增强活动, 对认识地震孕育过程和地震预测研究具有一定的启示意义。

关键词: 地震活动性, 巧家台阵, 2013年芦山地震, 2014年鲁甸地震

Abstract: A seismic network (Qiaojia network) of Twenty four seismometers operated by Institute of Geophysics, China Earthquake Administration was situated along the Zemuhe fault and the north end of Xiaojiang fault where is a part of the east boundary of the Chuan-Dian rhombus crust mass. Since the end of Feb., 2012 when Qiaojia network started to operate, the 20 April, 2013 Lushan MS7.0 earthquake and the 3 Agust, 2014 Ludian MS6.5 earthquake have occurred in the vicinity of Qiaojia network. The earthquake catalogue recorded by Qiaojia network since March, 2012 is used in this study. The temporal variation of earthquake count before the Lushan event and the Ludian event is analysed. The results are as follows: ① A very clear gradually increasing variation of the count of M 2.0 earthquakes within the region where all earthquakes recorded by the Qiaojia network coverage can be found before the Lushan event and the Ludian event, and the increasing range and duration of the count before the Ludian event are both larger than those before the Lushan event. ② In the region covered by Qiaojia network, for earthquakes with depth h 10 km a rising process of the count was manifest before both events, along with a nearly same duration of about five and a half manths, and for earthquakes with depth h>10 km a rising-dropping process of the count was manifest before the Lushan event before which the rising-dropping process showed again. The variation of the count for earthquakes with depth h 10 km is reverse to that for earthquakes with depth h>10 km; ③ Within and very close to the region covered by the Qiaojia network, the variation of the count manifests a rising process for earthquakes with depth h 10 km or h>10 km before the Lushan event and only for earthquakes with depth h 10 km before the Ludian event. The variation of the count manifests a weakening process for earthquakes with depth h>10 km before the Lushan event. It can be shown from above results that the seismicity within and very close to the region covered by the Qiaojia network showed a steeply rising change before both the Lushan event and the Ludian event. This phenomenon could be revelatory to understanding the process of earthquake development.

Key words: Seismicity, The 2013 Lushan earthquake, The 2014 Ludian earthquake, The Qiaojia network

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