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Keywords:

  • inner core;
  • shear wave;
  • quality factor

[1] Based on the high quality broadband data from Gräfenberg array in Germany, we recently detected a reliable PKJKP phase, for which four kinds of evidence (travel time, slowness, back-azimuth, and comparison with a pseudo-liquid inner core model) were simultaneously provided. Also, for the first time, a clear waveform of PKJKP was observed. This gives us an unprecedented opportunity to put constraints on the shear wave attenuation in the earth's inner core using body waves. In order to minimize the potential influence of dispersion and phase shift caused by mantle heterogeneity, we adopt an envelope modeling approach. Our results show that the estimated Qβ from the shear phase PKJKP is significantly larger (∼315 ± 150) than that from normal mode observations. Because PKJKP samples the deep inner core, this indicates an increase of Qβ with depth in the inner core, in agreement with what is generally observed for Qα.