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.

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The analysis of reverberation periodicities is shown to be a promising method to study local crustal structure. It is demonstrated with the help of numerical models, that for an average crust; a data length of only 8 to 12 sec is sufficient to derive a crustal model in contrast to about 40 sec or more needed in the Phinney's spectral ratio matching technique. Examples from numerical models of one- and two-layer crusts are presented. Analysis of five intermediate and deep focus earthquakes, recorded on magnetic tape at the Echery (ECH) observatory of the Institut de Physique du Globe of Strasbourg, shows that while the spectral ratios indicate little overall coherence, the periodicity corresponding to the total crustal thickness is evident in all cases. The possibility of deriving a detailed crustal model is also discussed with the help of results from one of the above events.

Behavior of P, S and ScS residuals as well as those of differential travel times of ScS-P from the Jeffreys-Bullen tables are analyzed. The phases have been read from short-period records of the Antarctic station, Dumont d'Urville (DRV); the earthquakes originating in New Hebrides, Fiji-Tonga, and Banda Sea regions. P residuals from all regions show a mean value of about −1 sec. On the contrary, S and ScS residuals, well correlated among themselves, show important regional as well as focal-depth dependence. ScS-P residuals from shallow and intermediate shocks are largely positive for New Hebrides and largely negative for Banda Sea; those from intermediate shocks are moderately positive for Fiji-Tonga. The anomalies disappear at depths greater than about 200 km. Upper mantle shear velocity models are presented for the three regions. The models are discussed in relation to a sinking lithosphere.

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