Spectrum of short-period core phases in relation to the attenuation in the mantle

Abstract

Spectral analysis is made of the records of the short-period reflected core phases from array stations at Tonto Forest, Arizona. Three earthquakes having Δ = 32.5°, 49.0°, and 62.8° are studied. Spectral ratios of ScS to ScP and PcS to PcP are calculated in order to estimate the differential effect of attenuation on P and S waves. The possible maximum value of average Q for shear in the mantle, Q[bar]_ β, is about 324 for the period range 1.5 to 5 sec. Using the value of inline image, average Q for P waves, that was previously estimated as 435 through the spectral analysis of PcP phase Q[bar]_ β and Q[bar]_α/Q[bar]_ β can be estimated at 230 and 1.90, respectively.

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