• ISSN 2097-1893
  • CN 10-1855/P

2020年10月22日四川北川MS4.7地震强震动特征分析

Strong-motion recordings in MS4.7 Beichuan, Sichuan earthquake on October 22, 2020

  • 摘要: 2020年10月22日11时03分37秒四川省绵阳市北川县发生MS4.7地震,四川强震动台网与预警烈度速报台网在震区建成较密集的台站,获取了532组三分量加速度记录,有助于开展区域地震动衰减和地震动特征研究. 本文对强震记录进行常规处理后计算出强震动记录的相关参数,利用克里金插值方法得到地震动峰值加速度PGA和峰值速度PGV的空间分布图,长轴呈北西—南东方向. 分析强震动记录PGA、PGV 随距离的衰减规律,与常用衰减关系预测值进行对比,此次地震 PGA 的衰减特性与俞言祥和汪素云(2006)提出的中国西部地区水平向基岩加速度衰减关系有较好的一致性. 北川MS4.7地震获得的密集强震动记录为建立区域衰减关系,以及开展基于经验格林函数方法(EGFM)再现大震强地震动场展布等研究提供了重要的数据支撑.

     

    Abstract: On October 22, 2020, an earthquake with magnitude 4.7 occurred in Beichuan County, Sichuan Province. 532 sets of three-component acceleration records have been obtained by Sichuan strong motion network, which contribute to the study of regional ground motion attenuation and ground motion characteristics. After the conventional processing of strong motion records, the relevant parameters of strong motion records have been calculated. The spatial distribution maps of PGA and PGV are obtained by Kriging interpolation method, and the long axis is NE-SW direction. The attenuation law of PGA and PGV of strong motion records with distance is analyzed. Through comparison and analysis with three commonly used attenuation relationship prediction values, such as attenuation relationship of Eastern strong earthquake area established by the fifth generation zoning map, it can be seen that PGA and PGV of strong motion records are similar to those of this earthquake. The attenuation characteristics of the model are in good agreement with the attenuation relationship of horizontal bedrock acceleration proposed by Yu and Wang (2006). The dense strong motion records obtained from the Beichuan MS4.7 earthquake provide important data support for establishing regional attenuation relationships and carrying out studies based on the empirical Green function method (EGFM) to reproduce the distribution of strong ground motions of large earthquakes.

     

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