Development of a Time-Domain, Variable-Period Surface-Wave Magnitude Measurement Procedure for Application at Regional and Teleseismic Distances, Part II: Application and Ms–mb Performance
Development of a Time-Domain, Variable-Period Surface-Wave Magnitude Measurement Procedure for Application at Regional and Teleseismic Distances, Part II: Application and Ms–mb Performance
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DOI：
10.1785/0120050056
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发表时间：
2006-04
影响因子：
3
通讯作者：
J. Bonner;D. Russell;D. Harkrider;D. Reiter;R. Herrmann
中科院分区：
文献类型：
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作者：
J. Bonner;D. Russell;D. Harkrider;D. Reiter;R. Herrmann
本文第一部分发展的Russell面波震级公式和本文讨论的M_S(Vmax)测量技术，为估算区域和远震距离的变周期面波震级提供了一种新的方法。M_S(Vmax)测量方法包括对中心周期为8到25秒的数据应用巴特沃斯带通滤波器。滤光器的设计有助于消除区域和远震距离处非弥散的艾里震相的影响。我们在所有的可变周期带中寻找最大幅度，然后使用Russell公式来计算面波震级。在这篇配套文章中，我们通过使用三个不同数据集的应用程序来演示该方法的功能。第一个应用程序利用了一个包含地中海地区大地震的数据集。结果表明，M_S(VMAX)技术提供的区域和远震面波震级估计结果基本一致，除了与−0.002级单位/度的小距离相关性外。我们还发现，M_S(Vmax)的估计值与Rezapour和Pearce(1998年)和Vanĕk等人在远震距离上应用的公式相差不到0.1个震级单位。(1962)。在该方法的第二次和第三次应用中，我们证明了M_S(Vmax)与M_b的测量能够很好地分离内华达州和罗普诺尔试验场的爆炸和地震人口。在内华达州的试验场，我们的技术导致了爆炸人群中的两次地震的错误分类。我们还确定，与我们之前使用校准的区域震级公式进行的研究相比，新技术将震级估计中的散布减少了25%。对于Lop Nor试验场，我们没有错误分类的爆炸或地震；然而，数据不那么全面。对欧亚地震和爆炸资料的初步分析表明，观测到的M_S(Vmax)和M_b(M_B)和M_b(Lt；5)资料具有相似的斜率，因此资料在较低震级时不收敛。这些结果表明，利用Russell(2006)公式和M_S(Vmax)测量技术可以在较低震级下实现爆炸与地震的区分。
The Russell surface-wave magnitude formula, developed in Part I of this two-part article, and the M_s(VMAX) measurement technique, discussed in this article, provide a new method for estimating variable-period surface-wave magnitudes at regional and teleseismic distances. The M_s(VMAX) measurement method consists of applying Butterworth bandpass filters to data at center periods between 8 and 25 sec. The filters are designed to help remove the effects of nondispersed Airy phases at regional and teleseismic distances. We search for the maximum amplitude in all of the variable-period bands and then use the Russell formula to calculate a surface-wave magnitude. In this companion article, we demonstrate the capabilities of the method by using applications to three different datasets. The first application utilizes a dataset that consists of large earthquakes in the Mediterranean region. The results indicate that the M_s(VMAX) technique provides regional and teleseismic surface-wave magnitude estimates that are in general agreement except for a small distance dependence of −0.002 magnitude units per degree. We also find that the M_s(VMAX) estimates are less than 0.1 magnitude unit different than those from other formulas applied at teleseismic distances such as Rezapour and Pearce (1998) and Vanĕk et al. (1962). In the second and third applications of the method, we demonstrate that measurements of M_s(VMAX) versus m_b provide adequate separation of the explosion and earthquake populations at the Nevada and Lop Nor Test Sites. At the Nevada Test Site, our technique resulted in the misclassification of two earthquakes in the explosion population. We also determined that the new technique reduces the scatter in the magnitude estimates by 25% when compared with our previous studies using a calibrated regional magnitude formula. For the Lop Nor Test Site, we had no misclassified explosions or earthquakes; however, the data were less comprehensive. A preliminary analysis of Eurasian earthquake and explosion data suggest that similar slopes are obtained for observed M_s(VMAX) versus m_b data with m_b <5. Thus the data are not converging at lower magnitudes. These results suggest that the discrimination of explosions from earthquakes can be achieved at lower magnitudes using the Russell (2006) formula and the M_s(VMAX) measurement technique.