Seismic hazard from instrumentally recorded, historical and simulated earthquakes: Application to the Tibet–Himalayan region
Seismic hazard from instrumentally recorded, historical and simulated earthquakes: Application to the Tibet–Himalayan region
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DOI：
10.1016/j.tecto.2015.07.004
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发表时间：
2015-08
期刊：
影响因子：
2.9
通讯作者：
V. Sokolov;A. Ismail-Zadeh
中科院分区：
文献类型：
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作者：
V. Sokolov;A. Ismail-Zadeh
我们提出了一种评估区域地震危险性的新方法，该方法考虑了观测到的（仪器记录的和历史的）地震，以及模拟的地震事件的时间明显长于观测的时间。我们将这种方法应用于西藏-喜马拉雅地区的概率地震危险性分析（PSHA）。与地球物理和大地测量数据一致的大震级合成事件以及观测到的地震被用于蒙特卡洛 PSHA。用于危险评估的地震场景是随机生成的，以对地震活动的震级和空间分布以及每个地震事件的地面运动分布进行采样。对 475 年重现期估计的峰值地面加速度值表明，如果 PSHA 中考虑模拟地震活动的长期记录，则与西藏 - 喜马拉雅地区大型事件相关的危险水平会显着增加。 2008 年汶川 7.9 级地震的震级和震源位置均在我们分析中接受的震源模型描述的范围之内。我们使用解聚合技术分析了在地震震中区域获得的地面运动数据与获得的 PSHA 估计之间的关系。所提出的方法可以更好地了解可能发生的大规模事件引起的地面震动，并且可用于风险评估、地震工程目的和应急计划。
We present a new approach to assessment of regional seismic hazard, which accounts for observed (instrumentally recorded and historic) earthquakes, as well as for seismic events simulated for a significantly longer period of time than that of observations. We apply this approach to probabilistic seismic hazard analysis (PSHA) for the Tibet–Himalayan region. The large magnitude synthetic events, which are consistent with the geophysical and geodetic data, together with the observed earthquakes are employed for the Monte-Carlo PSHA. Earthquake scenarios for hazard assessment are generated stochastically to sample the magnitude and spatial distribution of seismicity, as well as the distribution of ground motion for each seismic event. The peak ground acceleration values, which are estimated for the return period of 475 yr, show that the hazard level associated with large events in the Tibet–Himalayan region significantly increases if the long record of simulated seismicity is considered in the PSHA. The magnitude and the source location of the 2008 WenchuanM= 7.9 earthquake are among the range of those described by the seismic source model accepted in our analysis. We analyze the relationship between the ground motion data obtained in the earthquake's epicentral area and the obtained PSHA estimations using a deaggregation technique. The proposed approach provides a better understanding of ground shaking due to possible large-magnitude events and could be useful for risk assessment, earthquake engineering purposes, and emergency planning.