Comparison of the Empirical Green's Spatial Derivative Method and Empirical Green's Function Method
Comparison of the Empirical Green's Spatial Derivative Method and Empirical Green's Function Method
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经验格林空间导数法与经验格林函数法的比较
DOI：
10.1785/0120100114
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发表时间：
2011
影响因子：
3
通讯作者：
Y. Hisada
中科院分区：
文献类型：
--
作者：
M. Ohori;Y. Hisada
摘要在我们以前的研究（Ohori和Hisada，2006）中，我们模拟了2001年日本兵库县北部地震主震（MJ 5.4）的强震记录，根据经验绿色张量空间导数（EGTD）估计的11个余震（MJ 3.5-4.7）的数据。在较长的时间内，在源距最近的台站观测到的波形与计算出的波形之间的一致性令人满意，并且振幅被很好地再现。为了进一步评估EGTD估计，重要的是将EGTD方法的结果与已广泛用于强震模拟的经验绿色函数（EGF）方法的结果进行比较。在这项研究中，我们比较了使用EGTD方法与EGF方法获得的强震模拟结果。在EGF模拟中，我们通过校正两次事件之间的辐射图系数的差异来计算每个余震的主震合成。对合成波形与观测资料的相对误差分别进行了S波主体部分、S波尾波部分和全波形的评价。用EGF方法模拟的结果表明，大多数余震都能较好地再现观测资料，尤其是S波主体部分，但当震源位于SH波或SV波辐射图的节点附近时，会高估余震的振幅。与EGF方法相比，EGTD方法消除了EGF方法对余震选择的依赖性，不仅对S波部分，而且对S波尾波部分都提供了稳定可靠的结果。
Abstract In our previous study (Ohori and Hisada, 2006), we simulated the strong-motion records of the mainshock ( M J 5.4) of the 2001 Hyogo-ken Hokubu earthquake, Japan, on the basis of the empirical Green’s tensor spatial derivative (EGTD) estimated from data of 11 aftershocks ( M J 3.5–4.7). The agreement between the observed and calculated waveforms at the closest station in source distance was satisfactory over a long duration, and the amplitude was well reproduced. To further evaluate the EGTD estimation, it is important to compare the results of the EGTD method with those of a similar approach, the empirical Green’s function (EGF) method, which has been used widely in strong-motion simulation. In this study, we compare the strong-motion simulation results obtained using the EGTD method with those obtained using the EGF method. In the EGF simulation, we calculate the mainshock synthesis from each aftershock by correcting for the difference in the radiation pattern coefficients between the two events. The relative errors of synthesized waveforms against observation data are evaluated for the S -wave main portion, S -wave coda portion, and full waveform. The simulation results obtained using the EGF method indicate that most aftershocks reproduce well the observation data, especially for the S -wave main portion, but overestimate the amplitude when the sources are located near the node of the SH -wave or SV -wave radiation pattern. It seems that the EGTD method smooths the dependency of the EGF method on the aftershock selection and provides stable and reliable results in contrast to the EGF method, not only for the S -wave portion but also for the S -wave coda portion.