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Aki 提出的单次散射模型由于它的简单而显得很实用.作为单次散射模型的改进,本文表明应用多次散射模型也可给出一个简单可行的办法来估算一定地区地下介质的不均匀性.本文分别用尾波的强度和衰减求出与散射有关的 Q 因子.可以看到,尽管单次散射模型和多次散射模型两者给出了十分接近的结果,但后者显得更加合理并有其自相一致性.本文认为,无论运用哪个简化了的模型,方程(InA=α_1—Int—b_1t 或 InA=α_2—0.5lnt—b_2t)中的对数项是不可忽略的.本文应用北京地区地震台网资料,求出了频率在1Hz 左右北京地区 S 波的平均自由程,结果见表2.
Because of its simplicity, the single-scattering model proposed by Aki is very practical. As an improvement of the single-scattering model, this paper shows that using multiple scattering model can also give a simple and feasible method to estimate the inhomogeneity of underground media in a certain area In this paper, the Q-factor associated with scattering is calculated using the intensities and the decay of the coda, respectively. It can be seen that although both the one-shot and the multiple-scattering models give very close results, the latter seems to be more reasonable There is self-consistency .This paper argues that the logarithm of the equation (InA = α_1-Int-b_1t or InA = α_2-0.5lnt-b_2t) can not be neglected no matter which simplified model is used.In this paper, Regional seismic network data, found the frequency of about 1Hz S wave in Beijing free range, the results shown in Table 2.