Amplitudes of surface waves and magnitudes of shallow earthquakes
Amplitudes of surface waves and magnitudes of shallow earthquakes
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DOI：
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发表时间：
1945
影响因子：
3
通讯作者：
B. Gutenberg
中科院分区：
文献类型：
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作者：
B. Gutenberg
本文利用周期为20秒左右的面波振幅研究来改进远源浅源地震震级的计算。表3给出了台站的校正值;表4给出了震中距离影响的修正值。结果表明，当震中距在20° ~ 175°之间时，观测到的平均振幅与吸收系数k = 0.0003/km时的计算值相当吻合。对于完全位于太平洋海盆外部或内部的路径，k = 0.0002±每公里，而对于与其边界相切的路径，周期约为20秒的表面波的振幅可能由于能量的反射或折射而减少三分之二或更多（在极端情况下几乎减少十分之九）;这种浅震的地震图可被视为指示中间震源深度。
A study of amplitudes of surface waves having periods of about 20 seconds is employed to improve the calculation of magnitudes of distant shallow earthquakes. Table 3 gives station corrections; table 4, revised figures for the effect of epicentral distance. It is found that for epicentral distances between about 20° and 175° the average observed amplitudes correspond closely to those calculated with an absorption coefficient k = 0.0003 per km. For paths completely outside or inside the Pacific Basin, k = 0.0002± per km., while for paths tangent to its boundary the amplitudes of surface waves with periods of about 20 seconds may be reduced by two-thirds or more (in extreme cases by almost nine-tenths) through reflection or refraction of energy; such seismograms of shallow shocks may be taken as indicating intermediate depth of focus.