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Seismic Azimuthal Anisotropy Beneath the Eastern United States and its Geodynamic Implications
Geophysical Research Letters
  • Bin B. Yang
  • Yunhua Liu
  • Haider Dahm
  • Kelly H. Liu, Missouri University of Science and Technology
  • Stephen S. Gao, Missouri University of Science and Technology
Abstract

Systematic spatial variations of anisotropic characteristics are revealed beneath the eastern U.S. using seismic data recorded between 1988 and 2016 by 785 stations. The resulting fast polarization orientations of the 5613 measurements are generally subparallel to the absolute plate motion (APM) and are inconsistent with the strike of major tectonic features. This inconsistency, together with the results of depth estimation using the spatial coherency of the splitting parameters, suggests a mostly asthenospheric origin of the observed azimuthal anisotropy. The observations can be explained by a combined effect of APM-induced mantle fabric and a flow system deflected horizontally around the edges of the keel of the North American continent. Beneath the southern and northeastern portions of the study area, the E-W keel-deflected flow enhances APM-induced fabric and produces mostly E-W fast orientations with large splitting times, while beneath the southeastern U.S., anisotropy from the N-S oriented flow is weakened by the APM.

Department(s)
Geosciences and Geological and Petroleum Engineering
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2017 Blackwell Publishing Ltd, All rights reserved.
Publication Date
3-1-2017
Disciplines
Citation Information
Bin B. Yang, Yunhua Liu, Haider Dahm, Kelly H. Liu, et al.. "Seismic Azimuthal Anisotropy Beneath the Eastern United States and its Geodynamic Implications" Geophysical Research Letters Vol. 44 Iss. 6 (2017) p. 2670 - 2678 ISSN: 0094-8276
Available at: http://works.bepress.com/kelly-liu/103/