DOI: 10.1029/94gl01600. Anisotropy in the center of the inner core

Anisotropy in the center of the inner core

10.1029/94gl01600

Crossref journal-article

American Geophysical Union (AGU)

Geophysical Research Letters (13)

Abstract

We have assembled a collection of PKP data from broadband records of the Geoscope network. This collection is unique because, for the first time, it includes polar paths at epicentral distances between 172° and 177°, for which PKPDF samples the central part of the inner core. After Hilbert transforming the DF branch, the waveforms of PKPAB and PKPDF usually become very similar, and we measure differential travel times with an accuracy of a fraction of a second. The differential (AB‐DF) times for equatorial paths are close to those predicted by PREM, whereas for the polar paths, they are larger by 3 to 6 sec. Absolute DF times confirm that the effect is primarily in the inner core. These observations are compatible with a model of cylindrical anisotropy in the inner core with the axis of symmetry aligned with the Earth's spin axis and an amplitude of 3.5%. They require that the anisotropy extend to the central part of the inner core, confirming extrapolations made by Creager (1992) and ruling out models where anisotropy is confined to the outer 300 km of the inner core (Tromp, 1993).

Bibliography

Vinnik, L., Romanowicz, B., & Breger, L. (1994). Anisotropy in the center of the inner core. Geophysical Research Letters, 21(16), 1671â1674. Portico.

Authors 3

Lev Vinnik (first)
Barbara Romanowicz (additional)
Ludovic Breger (additional)

References 14 Referenced 78

10.1111/j.1365-246X.1978.tb05491.x
10.1038/356309a0
10.1016/0031-9201(81)90046-7
10.1029/GL008i006p00569
10.1029/GL013i013p01545
10.1038/305204a0
10.1029/90JB02370
10.1029/92GL02614
10.1029/92GL02614
{'key': 'e_1_2_1_11_1', 'first-page': '23', 'article-title': 'Inner core anisotropy in three dimensions', 'volume': '65', 'author': 'Su W.‐J.', 'year': '1994', 'journal-title': 'Seism. Res. Lett.'} / Seism. Res. Lett. / Inner core anisotropy in three dimensions by Su W.‐J. (1994)
10.1029/93JB03408
10.1038/366678a0
10.1029/GL013i013p01549
{'key': 'e_1_2_1_15_1', 'series-title': 'AGU Geodyn. Monograph', 'author': 'Zonnenshain L. P.', 'year': '1990'} / AGU Geodyn. Monograph by Zonnenshain L. P. (1990)

Dates

Type	When
Created	21 years, 7 months ago (Feb. 3, 2004, 10:32 p.m.)
Deposited	1 year, 11 months ago (Sept. 22, 2023, 5:32 p.m.)
Indexed	5 months, 2 weeks ago (March 19, 2025, 9:20 a.m.)
Issued	31 years, 1 month ago (Aug. 1, 1994)
Published	31 years, 1 month ago (Aug. 1, 1994)
Published Online	12 years, 9 months ago (Dec. 7, 2012)
Published Print	31 years, 1 month ago (Aug. 1, 1994)

Funders 0

None

BibTeX

@article{Vinnik_1994, title={Anisotropy in the center of the inner core}, volume={21}, ISSN={1944-8007}, url={http://dx.doi.org/10.1029/94gl01600}, DOI={10.1029/94gl01600}, number={16}, journal={Geophysical Research Letters}, publisher={American Geophysical Union (AGU)}, author={Vinnik, Lev and Romanowicz, Barbara and Breger, Ludovic}, year={1994}, month=aug, pages={1671–1674} }

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