Attenuation tomography of the upper inner core

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...

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Bibliographic Details
Published in:Journal of geophysical research. Solid earth 2017-04, Vol.122 (4), p.3008-3032
Main Authors: Pejić, Tanja, Tkalčić, Hrvoje, Sambridge, Malcolm, Cormier, Vernon F., Benavente, Roberto
Format: Article
Language:English
Subjects:
Attenuation
Bayesian analysis
Body waves
Correlation analysis
Damping
Earth
Earth core
Earth science
Frameworks
Geophysics
inner core
Mantle
Probability theory
Regional variations
Regularization
Rheological properties
Rheology
Seismology
Smoothing
Solidification
Texture
Thermal structure
Tomography
Wave attenuation
Waveforms
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Summary: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. Key Points Attenuation tomography of the inner core performed from a global data set of waveform correlated measurements Complex regional variations of attenuation The observed pattern of attenuation is not in agreement with commonly accepted spherical degree 1
ISSN:2169-9313
2169-9356
DOI:10.1002/2016JB013692