Source Rupture Process of the 2004 Chuetsu, Mid-Niigata Prefecture, Japan, Earthquake Inferred from Waveform Inversion with Dense Strong-Motion Data
Source Rupture Process of the 2004 Chuetsu, Mid-Niigata Prefecture, Japan, Earthquake Inferred from Waveform Inversion with Dense Strong-Motion Data
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DOI：
10.1785/0120080257
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发表时间：
2009-02
影响因子：
3
通讯作者：
K. Asano;T. Iwata
中科院分区：
文献类型：
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作者：
K. Asano;T. Iwata
摘要利用线性波形反演方法，从强震资料中估计了2004年日本新潟县中部中越地震的震源破裂过程。为了得到合适的绿色函数，通过模拟余震波形，建立了每个台站的一维速度结构模型。估计基岩顶部在断层西侧较深，而在东侧相对较浅。这一趋势与地震层析成像和微动阵列观测的其他研究相吻合。所得到的震源模型显示在震源附近的大滑移。逆走滑破裂起源于断裂深部，向上倾，向西南方向扩展。近地表滑动较小。两个测试证明，以检查所获得的源模型的稳定性。第一个测试检查可用站点数量对解决方案的影响，第二个测试检查目标波形类型的差异如何影响解决方案。观测站的数量影响滑移量的变化，在这种情况下，超过12个观测站似乎足以获得稳定的解。如果测站数量足够，并且绿色函数经过良好校准，则数据集中目标波类型的差异不会显著影响解。与单一速度结构模型相比，使用校准的速度结构模型获得的模型显示出清晰的高滑移区图像。
Abstract The kinematic source rupture process of the 2004 Chuetsu, mid-Niigata prefecture, Japan, earthquake, is estimated from strong-motion data by the linear waveform inversion method. In order to develop appropriate Green’s functions, one-dimensional velocity structure models for each station are constructed by modeling the aftershock waveforms. The estimated top of the bedrock is deeper at the western side of the fault and relatively shallow at the eastern side. This tendency coincides with other investigations of seismic tomography and microtremor array observations. The obtained source model shows large slips in the vicinity of the hypocenter. The reverse slipping rupture originated from the deeper part of the fault and propagated toward the up-dip and southwest directions. The near-surface slip is small. Two tests are demonstrated to check the stability of the obtained source model. The first test examines the effects of the number of available stations on the solution, and the second test examines how the difference in the target waveform type affects the solution. The number of stations affects the variation of slip amount, and more than 12 stations appear to be sufficient to obtain a stable solution in this case. The difference in the target wave type in the data set does not significantly affect the solution if the number of stations is sufficient and the Green’s functions are well calibrated. The model obtained using calibrated velocity structure models shows clear image of high-slip area compared to the model obtained using a single velocity structure model.