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地震 ›› 2018, Vol. 38 ›› Issue (4): 172-180.

• • 上一篇    

2014年5月云南盈江MS6.1地震序列横波分裂讨论

吴朋1, 秦敏2, 赵翠萍3, 苏金蓉1, 华卫3, 王宇航1   

  1. 1.四川省地震局, 四川 成都 610041;
    2.云南省地震局, 云南 昆明 650224;
    3.中国地震局地震预测研究所, 北京 100036
  • 收稿日期:2017-12-04 发布日期:2019-08-15
  • 作者简介:吴朋(1983-),男,四川南江人,工程师,主要从事数字地震学研究工作。
  • 基金资助:
    中国地震局测震台网青年骨干培养专项(20160522和20160521); 2017年中国地震局台站三结合课题(CEA-JC/3JH-162504)

Shear Wave Splitting Analysis of the 2014 Yingjiang MS6.1 Earthquake Sequence, Yunnan

WU Peng1, QIN Min2, ZHAO Cui-Ping3, SU Jin-Rong1, HUA Wei3, WANG Yu-Hang1   

  1. 1.Earthquake Administration of Sichuan Province, Chengdu 610041, China;
    2.Earthquake Administration of Yunnan Province, Kunming 650224, China;
    3.Institute of Earthquake Science, CEA, Beijing 100036, China
  • Received:2017-12-04 Published:2019-08-15

摘要: 2014年5月24日、 30日云南盈江地区先后发生了MS5.6和MS6.1地震。 采用质点运动判别与偏振分析相结合的方法测定了此次地震序列横波分裂参数, 即快波偏振方向和慢波延迟时间, 最后获得了4个台站的横波分裂参数。 震源区附近的两个台站KAC、 MNO快波偏振优势方向为NS向, 与区域主压应力轴方向一致。 在MS6.1地震发生后MNO台站快波偏振方向出现了紊乱现象, KAC台站快波偏振方向发生了偏转。 这4个台站的平均慢波延迟时间分布在1.50~4.47 ms/km。 靠近主震附近的KAC和MNO台的平均延迟时间均大于4.0 ms/km,表明距主震越近各向异性的程度越大。 MNO台站在MS6.1地震前慢波延迟时间的突然减小意味着临近主震前震源区地壳应力释放。

关键词: 横波分裂, 快横波偏振方向, 慢波延迟时间, 2014年盈江MS4.6地震

Abstract: The MS5.6 and 6.1 earthquakes occurred on May 24th and 30th, 2014 in Yingjiang area, Yunnan Province, respectively. We measured the shear wave splitting parameters: the polarization direction of fast shear wave and the delay time of slow shear wave of the Yingjiang earthquake sequence by the combined method of the particle motion discrimination and the polarization analysis. Finally,we obtained the shear waves splitting parameters at 4 seismic stations. The results show the dominant polarization direction of fast shear wave is NS at stations KAC and MNO around the focal region, which is in agreement with the direction of the regional principal compressive stress. The polarization direction of fast shear wave at station MNO became in disorder and that of KAC deflected after the MS6.1 earthquake. The average delay time of slow shear wave at the 4 stations is in the range of 1.50~4.47 ms/km. The average delay time is greater than 4.0 ms/km at stations KAC and MNO near the mainshock, which suggests the closer to the mainshock, the greater the degree of anisotropy. The delay time of slow shear wave reduced suddenly at station MNO before the MS6.1 earthquake, implying the crustal stress released in the focal region before the mainshock.

Key words: Shear wave splitting, Polarization direction of fast shear wave, Delay time of slow shear wave, The 2014 Yingjiang MS6.1 Earthquake Sequence

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