Abstract

In the present study, the scattering and intrinsic attenuation are separated using the S‐wave attenuation (Qβ) and coda‐wave attenuation (Qc) employing the Wennerberg (1993) method, and the frequency‐dependent Qs and Qi relations have been developed for the region. The Qi and Qs show the frequency‐dependent character in the frequency range 1.5–24 Hz. The average scattering and intrinsic relationships are obtained for the region as Qs=(31±1)f 1.04±0.02, Qs=(48±1)f 1.05±0.02, and Qs=(61±1)f 1.05±0.02 and as Qi=(68±1)f 0.95±0.06, Qi=(134±1)f 1.01±0.05, and Qi=(167±1)f 0.96±0.03 for lapse time windows of 30, 40, and 50 s, respectively. The quality factor for the P wave (Qα) and the S wave (Qβ) are estimated using the extended coda‐normalization method of Yoshimoto et al. (1993). The frequency dependence Qα and Qβ relationships are obtained as Qα=(25±1)f (1.24±0.04) for the P wave and Qβ=(58±1)f (1.16±0.04) for the S wave. The quality factor for the coda wave (Qc) is estimated using the single backscattering model of Aki and Chouet (1975). The comparison of Qβ and Qc with Qi and Qs shows that both Qi and Qs are lower than the Qβ, as well as Qc, at 30 s lapse time. As the lapse time increases, both Qi and Qs increase in such a manner that Qc will increase because it contains the effects of both. This agrees with the theoretical as well as the laboratory measurements. Also Qc is higher than Qβ; this supports the model given by Zeng et al. (1991), which predicts that the combination of Qi and Qs should be such that Qc is more than Qβ.

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