Tkalčić, Hrvoje, Belonoshko, Anatoly B., Muir, Jack B., Mattesini, Maurizio, Moresi, Louis, and Waszek, Lauren (2024) Imaging the top of the Earth’s inner core: a present-day flow model. Scientific Reports, 14. 8999.

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Abstract

Despite considerable progress in seismology, mineral physics, geodynamics, paleomagnetism, and mathematical geophysics, Earth’s inner core structure and evolution remain enigmatic. One of the most significant issues is its thermal history and the current thermal state. Several hypotheses involving a thermally-convecting inner core have been proposed: a simple, high-viscosity, translational mode, or a classical, lower-viscosity, plume-style convection. Here, we use state-of-the-art seismic imaging to probe the outermost shell of the inner core for its isotropic compressional speed and compare it with recently developed attenuation maps. The pattern emerging in the resulting tomograms is interpreted with recent data on the viscosity of iron as the inner core surface manifestation of a thermally-driven flow, with a positive correlation among compressional speed and attenuation and temperature. Although the outer-core convection controls the heat flux across the inner core boundary, the internally driven inner-core convection is a plausible model that explains a range of observations for the inner core, including distinct anisotropy in the innermost inner core.

Item ID:	84925
Item Type:	Article (Research - C1)
ISSN:	2045-2322
Copyright Information:	Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2024
Funders:	Australian Research Council (ARC)
Projects and Grants:	ARC grant DP220102815
Date Deposited:	18 Mar 2025 23:49
FoR Codes:	37 EARTH SCIENCES > 3706 Geophysics > 370609 Seismology and seismic exploration @ 50% 37 EARTH SCIENCES > 3706 Geophysics > 370604 Geodynamics @ 25% 49 MATHEMATICAL SCIENCES > 4999 Other mathematical sciences > 499999 Other mathematical sciences not elsewhere classified @ 25%
SEO Codes:	28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100%
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