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Seismological support for the metastable superplume model, sharp features, and phase changes within the lower mantle

Sun, Daoyuan and Helmberger, Don and Gurnis, Michael (2007) Seismological support for the metastable superplume model, sharp features, and phase changes within the lower mantle. Proceedings of the National Academy of Sciences of the United States of America, 104 (22). pp. 9151-9155. ISSN 0027-8424. PMCID PMC1890462. http://resolver.caltech.edu/CaltechAUTHORS:SUNpnas07b

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Abstract

Recently, a metastable thermal-chemical convection model was proposed to explain the African Superplume. Its bulk tabular shape remains relatively stable while its interior undergoes significant stirring with low-velocity conduits along its edges and down-welling near the middle. Here, we perform a mapping of chemistry and temperature into P and S velocity variations and replace a seismically derived structure with this hybrid model. Synthetic seismogram sections generated for this 2D model are then compared directly with corresponding seismic observations of P (P, PCP, and PKP) and S (S, SCS, and SKS) phases. These results explain the anticorrelation between the bulk velocity and shear velocity and the sharpness and level of SKS travel time delays. In addition, we present evidence for the existence of a D" triplication (a putative phase change) beneath the down-welling structure.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1890462/PubMed CentralArticle
ORCID:
AuthorORCID
Sun, Daoyuan0000-0003-4461-4664
Gurnis, Michael0000-0003-1704-597X
Additional Information:© 2007 by the National Academy of Sciences. Edited by Russell J. Hemley, Carnegie Institute of Washington, Washington, DC, and approved March 7, 2007 (received for review September 15, 2006). Published online before print April 10, 2007, 10.1073/pnas.0608160104 We thank two anonymous reviewers for helpful discussion and comments, which improved this article. The waveform data were obtained from Incorporated Research Institutions for Seismology. This work was supported by National Science Foundation Grant EAR-0456433. Author contributions: D.S. performed research; E.T., D.H., and M.G. contributed new reagents/analytic tools; and D.H. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/cgi/content/full/0608160104/DC1.
Group:Seismological Laboratory
Subject Keywords:core–mantle boundary; D"
Issue or Number:22
PubMed Central ID:PMC1890462
Record Number:CaltechAUTHORS:SUNpnas07b
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SUNpnas07b
Alternative URL:http://dx.doi.org/10.1073/pnas.0608160104
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9389
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:17 Dec 2007
Last Modified:02 Oct 2017 19:07

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