2013年乌鲁木齐MS5.6和MS5.1地震强地震动模拟研究

Ground motion simulation of 2013 Vrümqi MS5.6 and MS5.1 earthquakes

  • 摘要: 利用基于动力学拐角频率的随机有限断层法,针对2013年3月29日和8月30日乌鲁木齐发生的MS5.6和MS5.1两次地震,选择不同机构的震源参数对23个台站的45条强震记录进行强地震动模拟,对比分析加速度时程和反应谱,并计算模型偏差.通过与实际场点记录进行对比的结果显示:选取的不同机构震源参数模型得到的模拟加速度时程在持时和形状上与实际记录有一定差距,对于近震源的台站,模拟结果的峰值加速度(PGA)比观测结果小,对于稍远的台站,结果基本能够保持一致;而加速度反应谱,模拟结果与观测结果具有较好一致性; 随机有限断层模型的误差在±0.5以内,拟合效果较好,而且高频段的拟合效果要好于低频段;采用不同机构震源参数模型得到的模拟结果与观测结果得到的PGA分布特征较为一致,但模拟结果的峰值加速度要低于观测结果.

     

    Abstract: In this study, we simulated strong ground motion of two earthquakes with MS5.6 and MS5.1 occurred in Xinjiang Vrümqi in 2013 based on modified stochastic finite fault modeling with dynamic corner frequency. 45 strong ground motion records from 23 stations were chosen to simulate by different source parameters, and response spectrum and accelerograms were compared with the observed ones. The results show that simulated strong ground motion have some differences with observed data in duration and shape, and the value of simulated peak ground acceleration (PGA) is less than observed in near-source. For acceleration response spectrum, the simulated result is consistent with observed. The bias of stochastic finite fault is between ±0.5 suggesting a good agreement for high frequency. For different source parameters model, the distribution characteristic of simulated PGAs are consistent with observed, but the simulated PGAs are less than observed ones.

     

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