Phase velocity and Q of mantle Rayleigh waves
Phase velocity and Q of mantle Rayleigh waves
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DOI：
10.1111/j.1365-246x.1979.tb01009.x
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发表时间：
1979-07
影响因子：
2.8
通讯作者：
I. Nakanishi
中科院分区：
文献类型：
--
作者：
I. Nakanishi
我们分析了千岛群岛地震（1963年）及其最大余震、阿拉斯加地震（1964年）和十胜冲地震（1968年）产生的长周期瑞利波。反褶积技术已成功地应用于计算相速度和Q。我们发现瑞利波Qs的区域差异与区域相速度的变化密切相关，并获得了五个构造省的纯路径相速度和Q。瑞利波沿屏蔽区衰减沿着较小，在屏蔽区相速度较高，而在构造活动区衰减较大，在构造活动区相速度较低。对纯路径相速度进行Q校正后，相速度的区域差异明显减小。为了正确解释表面波频散和自由振荡周期，需要通过体波的宽带测量来研究Q的频率依赖性。虽然模式MM 8（安德森，Ben-Menahem & Archambeau）的Q值适合作为200 ~ 300 s周期范围内观测Q值的平均代表，但不同大圆路径的Q值差异很大，200 s以下周期的平均Q值低于MM 8。
Summary We analysed the long-period Rayleigh waves that were generated by the Kurile Islands earthquake (1963), its largest aftershock, the Alaskan (1964) and the Tokachi-oki (1968) earthquakes. A deconvolution technique has been successfully applied to calculate the phase velocity and Q. We found significant regional differences in Rayleigh wave Qs which are closely correlated with regional variations in phase velocity and obtained pure-path phase velocities and Q for five tectonic provinces. The Rayleigh waves suffer small attenuation along the shield region where the phase velocity is high and large attenuation over the tectonically active regions where the phase velocity is low. Applying the Q-correction to the pure-path phase velocities the regional differences in phase velocity are considerably reduced. Studies of the frequency dependence of Q by the broad-band measurements of body waves are required in order to interpret correctly surface wave dispersion and free oscillation periods. Although the Q of the model MM8 (Anderson, Ben-Menahem & Archambeau) is appropriate as an average representation of the observed Q in the period range from 200 to 300s, the differences for different great-circle paths are very large and the average Q values at periods below 200 s are lower than those of MM8.