Kinematic and Dynamic Inversion of the 2008 Northern Iwate Earthquake
Kinematic and Dynamic Inversion of the 2008 Northern Iwate Earthquake
复制标题
2008年岩手北部地震的运动学和动力反演
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
R. Madariaga
中科院分区：
文献类型：
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作者：
S. Ruiz;R. Madariaga
利用K-NET和KiK-net网络的强震记录，对2008年7月24日日本北方岩手中等深度地震进行了运动学和动力学反演。这次中等强度地震的破裂被模拟为一个简单的椭圆形斑块。最佳的解决方案发现比较观察到的和合成的记录，使用L2范数和邻域算法搜索最佳的解决方案，然后通过探索的解决方案空间与蒙特卡洛技术。破裂的几何形状，破裂速度，和滑动分布估计的运动学反演。通过动态反演获得了破裂几何形状、应力和摩擦参数。这两种方法收敛到非常相似的源模型，半短轴为4公里，最大滑动约4米，大应力降在30-45 MPa的范围内。破裂持续时间小于3 s，因为亚瑞利破裂传播速度非常高。最佳模型的能量释放率在23-36 MJ/m2范围内，对于这种规模的事件来说，这是一个相当大的值。对于运动学和动力学反演，我们发现了在一定误差范围内拟合强震数据的解族，证实了反演参数之间的强权衡。最后，我们证明了动力反演解受动力相似参数κ和地震矩M的控制。这两个参数定义了模型空间的一个区域，其中动态相似的模型以近似相同的失配拟合观测。
在线资料：比较所有现有台站的观测波形和合成波形以及观测地震图和合成地震图的傅立叶频谱的图。
We perform kinematic and dynamic inversion of the 24 July 2008 ( M w 6.8) Northern Iwate intermediate depth earthquake in Japan using strong‐motion records from the K‐NET and KiK‐net networks. The rupture of this moderate magnitude earthquake is modeled as a simple elliptical patch. The optimal solutions are found comparing observed and synthetic records using an L 2 norm and the neighborhood algorithm to search for the best solution, followed by an exploration of solution space with a Monte Carlo technique. The geometry of the rupture, rupture velocity, and slip distribution are estimated by kinematic inversion. The rupture geometry, stress, and friction parameters are obtained by dynamic inversion. Both approaches converge to very similar source models with semiminor axes of 4 km, maximum slip of about 4 m, and large stress drops in the 30–45 MPa range. Rupture duration was less than 3 s because of very high sub‐Rayleigh rupture propagation speeds. Energy release rate for the best models was in the range 23–36 MJ/m2, a rather large value for events of this size. For both kinematic and dynamic inversion we found families of solutions that fit the strong‐motion data within a certain error, confirming the strong trade‐off among inverted parameters. Finally, we demonstrate that dynamic inversion solutions are controlled by the dynamic similarity parameter κ and by seismic moment M . These two parameters define a region of model space where dynamically similar models fit the observations with approximately the same misfit.
Online Material: Figures that compare observed and synthetic waveforms for all available stations and comparison of Fourier spectrum of observed and synthetic seismograms.