Masters Theses

Abstract

"The Pn tomography method utilizes seismic waves that refract along the Moho interface to perform inversion in order to investigate velocity anomalies and seismic anisotropy in the uppermost mantle. Results from Pn tomography can provide important information about the composition, temperature, and tectonic processes beneath the study area. Over the past decades, numerous seismic and geologic studies have been conducted in the Colorado Plateau and its adjacent areas to reveal crustal and mantle structures and processes responsible for the diverse surface geological features and tectonic events that have occurred in this area. To investigate lateral variations in the uppermost mantle in terms of temperature, composition and orientation of anisotropic fabrics beneath Colorado Plateau and adjacent areas, the Pn tomography method was applied. The current research uses data from 468 local earthquakes recorded by 186 stations from the Incorporated Research Institutions for Seismology Data Management Center. A total of 2548 seismograms were used to invert the velocity and anisotropic structures. Resulting low velocity anomalies beneath the westernmost part of the CP suggest a high-temperature top mantle, probably as a result of active mantle upwelling and hot asthenosphere replacement of cold lithosphere. In contrast, the high velocity anomaly represents cool and stable uppermost mantle. In comparison with the shear wave splitting and shear stress results, the fast orientation of Pn wave anisotropy may reflect the extension direction of Basin and Range and Rio Grand Rift studies."--Abstract, page iii.

Advisor(s)

Gao, Stephen S.

Committee Member(s)

Liu, Kelly H.
Anderson, Neil L. (Neil Lennart), 1954-

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2014

Pagination

vii, 51 pages

Note about bibliography

Includes bibliographical references (pages 46-50).

Geographic Coverage

Colorado Plateau, United States

Rights

© 2014 Shengyao Cheng, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Seismic tomography -- Colorado PlateauEarthquake zones -- United States

Thesis Number

T 10506

Electronic OCLC #

894578314

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Thesis Location

 
COinS