Spectral ratio of short-period ScPand ScSphases in relation to the attenuation in the mantle beneath the Tasman Sea and the Antarctic Region

Four pairs of ScP and ScS phases recorded at the station Dumont d'Urville, Adelie Land, at the epicentral distance of about 50°, have been frequency analyzed. The slope of spectral ratio has been utilized to calculate the average value of Qβ in the mantle between the Tasman Sea and the station. With Qα/Qβ = 1.9, we estimate the average value 〈Qβ〉 = 380. This is much higher than the estimation by H. Kanamori of 230 for the mantle beneath southern Arizona and New Mexico.