Journal of Geophysical Research: Solid Earth
Tanja Pejic, 1; Hrvoje Tkalcic, 1; Malcolm Sambridge, 1; Vernon F. Cormier, 2; and Roberto Benavente, 1,3.
1 Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
2 Department of Physics, University of Connecticut, Storrs, Connecticut, USA
3 National Research Center for Integrated Natural Disaster Management, Santiago, Chile
The solidification of the Earth’s inner core shapes its texture and rheology, affecting the attenuation and scattering of seismic body waves transmitted through it. Applying attenuation tomography in a Bayesian framework to 398 high-quality PKIKP waveforms, we invert for the apparent Qp for the uppermost 400 km below the inner core boundary at latitudes 45∘S to 45∘N. We use damping and smoothing for regularization of the inversion, and it seems that the smoothing regularization combined with the discrepancy principle works better for this particular problem of attenuation tomography. The results are consistent with a regional variation in inner core attenuation more complex than hemispherical, suggesting coupling between inner core solidification and the thermal structure of the lowermost mantle.