Observations of exotic inner core waves

Waszek, Lauren, and Deuss, Arwen (2015) Observations of exotic inner core waves. Geophysical Journal International, 200 (3). pp. 1636-1650.

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Abstract

The seismic structure of Earth's inner core is highly complex, displaying strong anisotropy and further regional variations. However, few seismic waves are sensitive to the inner core and fundamental questions regarding the origin of the observed seismic features remain unanswered. Thus, new techniques to observe different types of inner core waves are imperative to improve data coverage. Here, we detail our method for detecting exotic inner core phases such as PKJKP and PKIIKP, using inner core compressional waves as proof of concept. We use phase weighted stacking on long period data from a global distribution of stations, and employ several synthetic methods, including normal mode summation and SPECFEM, to identify and confirm the inner core phases. We present evidence for two observations of exotic inner core compressional waves, and apply the technique to a previously detected inner core shear wave. A possible new inner core shear wave remains unconfirmed. Additionally, we show how our method is important for rejecting potential observations, and distinguishing between waves with similar traveltime and slowness. The method is most successful for detecting exotic inner core compressional waves, and will provide a new approach for studying the compressional wave structures in the upper inner core.

Item ID: 65364
Item Type: Article (Research - C1)
ISSN: 1365-246X
Keywords: Body waves; Seismic anisotropy; Seismic attenuation
Copyright Information: © The Authors 2015. Published by Oxford University Press on behalf of The Royal Astronomical Society.
Funders: University of Cambridge, European Research Council (ERC), Leverhulme Trust
Projects and Grants: ERC FP7/2007-2013, ERC grant agreement number 204995
Date Deposited: 21 Dec 2020 23:51
FoR Codes: 04 EARTH SCIENCES > 0404 Geophysics > 040407 Seismology and Seismic Exploration @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%
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