孙丽娜,齐玉妍,陈婷,王晓山. 2021. 震源机制和场地条件在河北地震影响场判定中的应用研究. 地震学报,43(4):508−520. doi: 10.11939/jass.20200133
引用本文: 孙丽娜,齐玉妍,陈婷,王晓山. 2021. 震源机制和场地条件在河北地震影响场判定中的应用研究. 地震学报,43(4):508−520. doi: 10.11939/jass.20200133
Sun L N,Qi Y Y,Chen T,Wang X S. 2021. Research on application of focal mechanism and site conditions in judgment of Hebei earthquake influence field. Acta Seismologica Sinica43(4):508−520. doi: 10.11939/jass.20200133
Citation: Sun L N,Qi Y Y,Chen T,Wang X S. 2021. Research on application of focal mechanism and site conditions in judgment of Hebei earthquake influence field. Acta Seismologica Sinica43(4):508−520. doi: 10.11939/jass.20200133

震源机制和场地条件在河北地震影响场判定中的应用研究

Research on application of focal mechanism and site conditions in judgment of Hebei earthquake influence field

  • 摘要: 震后应急工作中地震影响场的判定和快速给出较为合理的地震烈度分布图,是震后应急救援的重要依据,对于政府了解灾情、部署工作以及估算灾害损失都尤为重要,所以本文以此为研究目的,力求震后快速给出准确的地震烈度分布图。本文收集整理了河北地区中强地震的实际等震线图,将其与加入了震源机制解影响参数的烈度衰减关系计算得到的理论等震线图进行对比。结果显示:随着震级的增大,由衰减关系计算得到的等震线图与实际地震等震线图在高烈度区(≥Ⅶ度)相似度更高。另外,根据震后24小时内余震频度的空间变化,对极震区理论等震线修正后,其与实际等震线更加贴合,即理论计算烈度与实际调查烈度值更加接近。最后,对河北地区划分网格,根据地震动衰减关系计算震例对各个网格中心点产生的影响—基岩PGA。提取场地类别属性,考虑场地放大因子,完成基岩PGA到地表PGA的转换。将地表PGA换算成烈度,并与实际地震等震线图进行对比分析。结果表明,考虑了场地放大效应的地震影响场在高烈度区与实际等震线相似度很高,且相似度超过基于震源机制解的烈度衰减关系方法。

     

    Abstract: The determination of seismic influence field in post-earthquake work, a quickly gived reasonable map of seismic intensity distribution, was an important basis for emergency rescue after the earthquake and was important for the government to understand the disaster situation, deploy work and estimate the disaster loss. In this paper, the isoseismal maps of moderate strong earthquakes in Hebei Province were collected and sorted out, it was compared with the theoretical isotherm map generated by the regional earthquake intensity attenuation relationship based on the focal mechanism solution. The results show that, with the increase of magnitude, the similarity was higher between the theoretical isoseismal map and the actual isoseismal map in the high intensity area (≥Ⅶ), the theoretical isoseismal map was calculated by the attenuation relationship of seismic intensity with focal mechanism solution. In addition, according to the spatial variation of aftershock frequency within 24 hours after the earthquake, the theoretical isoseismal line in the polar region is modified, which is more consistent with the actual isoseismal line. That is to say, the theoretical calculated intensity is closer to the actual investigation intensity value. Finally, the grid of Hebei area was divided, and the bedrock PGA of the earthquake case on each grid center point was calculated according to the attenuation relationship of ground motion. Then, the site category attributes were extracted, considered site amplification factor, and the conversion of bedrock PGA to surface PGA was completed. The surface PGA was converted into intensity and compared with the actual earthquake isoseismal map. The results show that the similarity between the seismic influence field calculated by considering the site amplification effect and the actual isoseismal line was very high in the high intensity area, and the similarity is higher than the intensity attenuation relation method based on the focal mechanism solution.

     

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