Near‐fault strong motion complexity of the 2003 Bam earthquake (Iran) and low‐frequency ground motion simulation
Near‐fault strong motion complexity of the 2003 Bam earthquake (Iran) and low‐frequency ground motion simulation
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2003年伊朗巴姆地震的近断层强震动复杂性及低频地震动模拟
DOI：
10.1111/j.1365-246x.2007.03423.x
复制
发表时间：
2007
影响因子：
2.8
通讯作者：
Y. Hisada
中科院分区：
文献类型：
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作者：
M. Ghayamghamian;Y. Hisada
摘要
2003年12月26巴姆地震是发生在巴姆市地下的一次中等规模的走滑事件，造成26000多人死亡。唯一的近断层台站(BAM台)的记录显示，在几乎断层的正常方向上有明显的长周期脉冲，这表明近断层的前向方向性效应对巴姆市的严重破坏起到了作用。为了更好地描述BAM台站不同分量的观测运动，本研究模拟了长周期(0.1-1.5 Hz)的强地面运动，以回答震源参数中的一些模糊问题。为此，采用Hisada的运动学模型来模拟长周期地震动，该模型同时考虑了非均匀震源特征和地下地质条件。考察了以往研究提出的不同震源方案，并介绍了能够为不同部件的模拟运动和观测运动提供最佳拟合的最佳方案。对滑移模型、粗糙度和速度结构参数进行了优化，以使模拟和观测的速度时程和谱具有最好的拟合度。模拟的低频运动与观测的低频运动之间的良好一致性表明，成功地识别了巴姆地震的震源和滑动参数，并为模拟技术提供了良好的检验。此外，根据巴姆地震的近场和远场观测记录，进一步验证了所识别的震源参数和滑动模型的唯一性。模拟波形与观测波形具有较好的一致性，为模型验证和结果确认提供了基础。
SUMMARY
The 2003 December 26 Bam earthquake was an intermediate size strike-slip event that occurred beneath the Bam city, causing more than 26000 fatalities. The record of the only near-fault station (Bam station) shows a clear long-period pulse in almost fault normal direction suggesting a near-fault forward directivity effect contributing to the heavy damage observed in Bam city. In this study, the long-period (0.1–1.5Hz) strong ground motions were simulated to answer some ambiguities in source parameters for fully description of the observed motion in different components at Bam station. To this end, the Hisada's kinematic model accounting for both heterogeneous source characteristics and underground geology is applied to simulate the long-period ground motion. Different source scenarios suggested by previous studies are examined and the optimum scenario that could provide the best fitting between the simulated and observed motions for different components was introduced. The slip model and asperities as well as velocity structure parameters are optimized in order to have the best possible fit between the simulated and observed velocity time histories and spectra. The good agreements between the simulated and observed low-frequency motions indicate a successful identification of source and slip parameters of the Bam earthquake and provide a good test for the simulation technique. Furthermore, the uniqueness of the identified source parameters and the slip model is further checked against the observed near- and far-field recordings of the Bam earthquake. A good agreement between the simulated and the observed waveforms provides a base for model verification and results confirmation.
Sawada, Y.：“日本西南部山阴地区白垩纪至中新世火成岩的 Nd-Sr 系统学。”
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