A low attenuation layer in the Earth's uppermost inner core

Waszek, Lauren and Deuss, Arwen (2013) A low attenuation layer in the Earth's uppermost inner core. Geophysical Journal International, 195 (3). pp. 2005-2015. ISSN ISSN: 0956-540X, ESSN: 1365-246X DOI https://doi.org/10.1093/gji/ggt368

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Abstract

The attenuation structure of the Earth's inner core, in combination with the velocity structure, provides much insight into its rheological and mineralogical properties. Here, we use a large data set of PKIKP/PKiKP amplitude ratios to derive attenuation models for the upper 100 km of the inner core, incorporating the effects of velocity models calculated using the same data set. We confirm that the upper inner core is hemispherical in attenuation, with stronger attenuation in the east hemisphere. We also observe, for the first time, a low attenuation upper layer of approximately 30 km thickness throughout the top of the inner core. Attenuation increases beneath this layer, and then gradually decreases going deeper into the inner core. Although the data appear to show attenuation anisotropy below 57.5 km depth in the west, we find that this can be explained by the velocity models alone, with no requirement for attenuation anisotropy in the upper inner core.

Item Type:	Article
Additional Information:	© The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.
Uncontrolled Keywords:	2013AREP; IA66;
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access
Journal or Publication Title:	Geophysical Journal International
Volume:	195
Page Range:	pp. 2005-2015
Identification Number:	https://doi.org/10.1093/gji/ggt368
Depositing User:	Sarah Humbert
Date Deposited:	13 Feb 2014 10:34
Last Modified:	13 Jul 2014 21:15
URI:	http://eprints.esc.cam.ac.uk/id/eprint/2956

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