孙楠, 高原, 赵小艳, 苏有锦, 刘庚, 邬成栋. 2017: 盈江MS6.1地震序列近场横波分裂研究. 地震学报, 39(1): 34-46. DOI: 10.11939/jass.2017.01.004
引用本文: 孙楠, 高原, 赵小艳, 苏有锦, 刘庚, 邬成栋. 2017: 盈江MS6.1地震序列近场横波分裂研究. 地震学报, 39(1): 34-46. DOI: 10.11939/jass.2017.01.004
Sun Nan, Gao Yuan, Zhao Xiaoyan, Su Youjin, Liu Geng, Wu Chengdong. 2017: Near-field shear-wave splitting of 2014 Yingjiang MS6.1 earthquake sequence. Acta Seismologica Sinica, 39(1): 34-46. DOI: 10.11939/jass.2017.01.004
Citation: Sun Nan, Gao Yuan, Zhao Xiaoyan, Su Youjin, Liu Geng, Wu Chengdong. 2017: Near-field shear-wave splitting of 2014 Yingjiang MS6.1 earthquake sequence. Acta Seismologica Sinica, 39(1): 34-46. DOI: 10.11939/jass.2017.01.004

盈江MS6.1地震序列近场横波分裂研究

Near-field shear-wave splitting of 2014 Yingjiang MS6.1 earthquake sequence

  • 摘要: 使用横波分裂系统分析方法(SAM), 对2014年5月30日盈江MS6.1地震震区内多个近场流动台站记录到的大量波形数据进行横波分裂研究. 研究结果表明, 盈江MS6.1地震序列的快S波偏振方向为近NS向, 与区域主压应力方向一致. 主震发生后, 由于震源区应力状态的调整, 卡场台(KAC)快S波偏振方向发生逆时针偏转, 勐弄台(MNO)快S波偏振方向离散度减小, 并且由于受到研究区内断裂的影响, MNO台偏振方向较KAC台偏振方向更加离散. KAC台和MNO台的慢S波时间延迟均表现出主震发生前短时间内突然减小, 震后逐渐增大的变化特征, 这意味着临震前震源区地壳应力的释放和震后地壳应力的增强, 预示了后续余震的持续发生. 地震序列时间延迟平均滑动曲线起伏振荡, 表明了余震的发生伴随着震源区地壳应力的不断调整.

     

    Abstract: SAM (systematic analysis method of shear-wave splitting) has been applied to numerous waveform data recorded by near-field mobile seismic stations of Yingjiang MS6.1 earthquake sequence occurred on May 30, 2014. The results showed that the polarization of fast shear-wave of the earthquake sequence was consistent with regional principal compressive stress of NS trending. The polarization of fast shear-wave has a counterclockwise deflection at the station KAC, and dispersion decrease at the station MNO due to the adjustment of stress state in seismic region after the main shock. Influenced by faults of the studied area, the polarization of fast shear-wave at the station MNO presents a more discrete state compared to that of KAC. The time-delays of slow shear-wave at the stations KAC and MNO both present the feature of sudden contraction before the main shock and increase after the event, which means release and enhancement of crustal stress before and after the earthquake, and also indicates constant occurrence of aftershocks. The oscillation of time-delay curves suggests that the occurrence of aftershocks is accompanied by continuous adjustment of crustal stress in seismic region.

     

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