Waveform search for the innermost inner core

Cormier, Vernon F.; Stroujkova, Anastasia

doi:10.1016/j.epsl.2005.05.016

Cited by 44 publications

(47 citation statements)

References 17 publications

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“…It turns out that, with the presently available data, the exact nature of the anisotropy in the innermost inner core is still hard to resolve and that the three families of models may be derived from the same PKP data, depending on data processing and assumptions used (Calvet et al, 2006). A sharp discontinuity at the top of the innermost inner core could not be detected (Cormier and Stroujkova, 2005;Garcia et al, 2006;Leyton et al, 2005;Niu and Chen, 2008). A sharp discontinuity at the top of the innermost inner core could not be detected (Cormier and Stroujkova, 2005;Garcia et al, 2006;Leyton et al, 2005;Niu and Chen, 2008).…”

Section: The Innermost Inner Corementioning

confidence: 91%

“…This central, high-Q zone approximately corresponds to the innermost inner core ( Figure 13) and could correspond to a different fabric (Cormier and Stroujkova, 2005). This central, high-Q zone approximately corresponds to the innermost inner core ( Figure 13) and could correspond to a different fabric (Cormier and Stroujkova, 2005).…”

Section: P-wave Attenuation: Depth Dependence and Hemispherical Variamentioning

confidence: 98%

See 1 more Smart Citation

Deep Earth Structure: The Earth’s Cores

Souriau

Calvet

2015

Treatise on Geophysics

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Section: The Innermost Inner Corementioning

confidence: 91%

Section: P-wave Attenuation: Depth Dependence and Hemispherical Variamentioning

confidence: 98%

Deep Earth Structure: The Earth’s Cores

Souriau

Calvet

2015

Treatise on Geophysics

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“…Ishii and Dziewoń ski (2002); Beghein and Trampert, 2003, and attenuation, e.g. Li and Cormier (2002); Cormier and Stroujkova, 2005, in the inner core, although Lythgoe et al (2014) find that an innermost inner core is not required to explain PKIKP travel times. A review of studies on the inner core structure and dynamics can be found in e.g.…”

Section: Attenuationmentioning

confidence: 94%

Bayesian inversion of free oscillations for Earth’s radial (an)elastic structure

Wit

Käufl

Valentine

et al. 2014

Physics of the Earth and Planetary Interiors

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“…Early studies using either of these techniques (Morelli et al, 1986;Woodhouse et al, 1986;Creager, 1992) proposed that the seismic velocity anisotropy in the inner core was both laterally invariant and depth-independent and that the axis of cylindrical anisotropy is aligned with Earth's rotation axis. More recent body wave studies have built up a picture of an inner core with a degree one 'hemispherical' structure (Tanaka & Hamaguchi, 1997;Creager, 1999;Oreshin & Vinnik, 2004) and a distinct innermost inner core where the anisotropy axis is at an angle of 45 • to the anisotropy axis in the rest of the inner core (Ishii & Dziewonski, 2002;Cormier & Stroujkova, 2005;Cao & Romanowicz, 2007;Sun & Song, 2008).…”

Section: Introductionmentioning

confidence: 99%

Stratified anisotropic structure at the top of Earth's inner core: A normal mode study

Irving

Deuss

2011

Physics of the Earth and Planetary Interiors

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Please cite this article as: Irving, J.C.E., Deuss, A., Stratified anisotropic structure at the top of Earth's inner core:a normal mode study, Physics of the Earth and Planetary Interiors (2010), doi:10.1016/j.pepi.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Page 1 of 40A c c e p t e d M a n u s c r i p tWe probe the isotropic layer at the top of Earth's inner core using normal modes. Normal mode data are compatible with an isotropic layer of up to 250km thick. Normal modes can therefore be reconciled with previous body wave studies. We further show seismic data support the presence an S-wave isotropic layer. *HighlightsPage 2 of 40 A c c e p t e d M a n u s c r i p t AbstractBody wave studies support the presence of an isotropic layer at the top of the inner core. Recent normal mode models of inner core anisotropy do not contain such a layer, but instead have anisotropic structure extending to the inner core boundary. Here, we use full-coupling of normal mode oscillations sensitive to inner core structure in order to investigate the discrepancy between models of the inner core developed using these two different types of data. We impose an isotropic layer onto existing normal mode models of inner core anisotropy, and calculate frequencies, quality factors and synthetic seismograms for radial modes, PKIKP modes and PKJKP modes. Using full-coupling allows us to make the first simulations of the effect of an isotropic layer on radial modes.The presence of an uppermost isotropic layer has an effect on the frequencies and attenuation of normal modes. By calculating the misfit between data from four large earthquakes and synthetic seismograms created for models of the inner core with isotropic layers of varying thickness, we find that normal mode data are compatible with the presence of an isotropic layer of up to 250km thickness at the top of the inner core. Thus, normal modes can be reconciled with previous body wave studies. The influence of such a layer on PKJKP modes is the only way that S-wave isotropy at the top of the inner core can currently be studied;we show, for the first time, that seismological data support the presence an S-wave isotropic layer.

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Waveform search for the innermost inner core

Cited by 44 publications

References 17 publications

Deep Earth Structure: The Earth’s Cores

Deep Earth Structure: The Earth’s Cores

Bayesian inversion of free oscillations for Earth’s radial (an)elastic structure

Stratified anisotropic structure at the top of Earth's inner core: A normal mode study

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