郭蕾,孙丽娜,周依,王宁. 2021. 唐山地区近十年地震的重定位研究. 地震学报,43(6):706−715. doi: 10.11939/jass.20210029
引用本文: 郭蕾,孙丽娜,周依,王宁. 2021. 唐山地区近十年地震的重定位研究. 地震学报,43(6):706−715. doi: 10.11939/jass.20210029
Guo L,Sun L N,Zhou Y,Wang N. 2021. Relocation of earthquakes in Tangshan area in the recent decade. Acta Seismologica Sinica43(6):706−715. doi: 10.11939/jass.20210029
Citation: Guo L,Sun L N,Zhou Y,Wang N. 2021. Relocation of earthquakes in Tangshan area in the recent decade. Acta Seismologica Sinica43(6):706−715. doi: 10.11939/jass.20210029

唐山地区近十年地震的重定位研究

Relocation of earthquakes in Tangshan area in the recent decade

  • 摘要: 分别运用双差定位法、结合波形互相关的双差定位法和结合波形互相关的双差层析成像法,对唐山地区2010年1月至2020年7月河北地震台网记录的4 874个地震事件进行重定位。结果表明:结合波形互相关的双差层析成像法的定位精度高于其它两种方法,地震走时均方根残差由初始的0.71降至0.27;重定位后的震中分布更加集中,线性分布更明显,优势分布方向为NE向,与该区域断层走向基本一致;重定位后震源深度主要集中在5—15 km,分布形态更接近于正态分布,结果更加合理。从重定位后的震中空间分布可见在唐山—古冶断裂东侧有一个NNE向的高倾角小震密集带,近年来小震活动频繁,分析认为该区域的局部应力较高,构造活动较强,推测在唐山—古冶断裂东端点可能存在隐伏断层,该区域地震的发生与其深部活动有关。

     

    Abstract: We relocated 4 874 earthquakes totally which were recorded by Hebei seismic network in Tangshan area during the period between January of 2010 and July of 2020 by using the double-difference relocation method, the double-difference relocation method combined with waveform cross-correlation, and the double-difference tomography method combined with the waveform cross-correlation, respectively. The comparison of the location results by the three relocation methods suggests that the double-difference tomography method combined with the waveform cross-correlation could produce much higher resolution hypocentral parameters than those from the other two methods. As a result, the root-mean-square (RMS) of traveltime residuals were greatly reduced from 0.71 s to 0.27 s. In map view the relocated earthquakes are more concentrated on obvious strips around the faults, and the dominant distribution direction is NE, which is basically consistent with the fault strike in this area. The result is more reasonable in depth distribution with focal depth mainly concentrated in 5−15 km, and the distribution pattern appears as a nearly normal distribution. From the spatial distribution of the epicenters after relocation, it can be seen that there is a small earthquake dense zone with steep dip angle in NNE direction on the east of the Tangshan-Guye fault, indicating that the stress level is high and the tectonic activity is strong in this local area. Therefore it is speculated that there may be a hidden fault at the eastern end of the Tangshan-Guye fault, and the occurrence of earthquake in this region is related to its deep activities.

     

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