Doctoral Dissertations

Keywords and Phrases

Anisotropy; Fast orientations; Splitting parameters

Abstract

"This study represents the first multi-station investigation of azimuthal anisotropy beneath the interior of north central Africa, including Libya and adjacent regions, using shear wave splitting (SWS) analysis. Data used in the study include recently available broadband seismic data obtained from 15 stations managed by the Libyan Center for Remote Sensing and Space Science, and those from five other stations at which data are publicly accessible. A total of 583 pairs of high-quality SWS measurements utilizing the PKS, SKKS, and SKS phases demonstrate primarily N-S fast orientations with an average splitting delay time of approximately 1.2 s. An absence of periodic azimuthal variation of the observed splitting parameters indicates the presence of simple anisotropy, and lack of correlation between surficial features and the splitting parameters suggests that the origin of the observed anisotropy is primarily asthenospheric. This conclusion is enhanced by non-periodic azimuthal variation of the splitting parameters observed at one of the stations located near the boundary of areas with different anisotropic properties. This research interprets the observed anisotropy to be the consequence of northward movement of the African plate relative to the asthenosphere toward the Hellenic and Calabrian subduction zones. Local variance in fast orientations may be attributable to flow deflection by the northern edge of the African continental root. The observations provide critical and previously lacking constraints on mantle dynamic models in the vicinity of the convergent boundary between the African and Eurasian plates"--Abstract, page iv.

Advisor(s)

Liu, Kelly H.
Gao, Stephen S.

Committee Member(s)

Eckert, Andreas
Yang, Wan
Anderson, Neil L. (Neil Lennart), 1954-

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Sponsor(s)

Benghazi University of Libya

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2016

Pagination

xi, 95 pages

Note about bibliography

Includes bibliographic references (pages 37-42).

Geographic Coverage

Africa

Rights

© 2016 Awad Abdussalam Henish Lemnifi, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

AnisotropyShear waves -- MeasurementGeology -- Africa

Thesis Number

T 10916

Electronic OCLC #

952596113

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Dissertation Location

 
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