Abstract
The internal friction of ice near its melting point has been measured in the Athabasca glacier for Rayleigh waves from 0.025 to 0.18 kHz, for P waves from 0.12 to 1.0 kHz, and for S waves from 0.12 to 0.68 kHz. The mean Q for Rayleigh waves was 28., for S waves 23., and for P waves 65. From the attenuation data, it is shown that the internal friction in pure dilatation is much less than in pure shear. On this basis the Rayleigh and S-wave data may be reduced to equivalent P-wave attenuation coefficients, yielding an attenuation spectrum that extends from 0.025 to 1.0 kHz. Additional measurements by Westphal extend the spectrum to 5.0 kHz. These measurements supplement the work of Kuroiwa and permit one to conclude that the attenuation mechanism is most probably grain-boundary slip.
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