Electronic Theses and Dissertations

Identifier

6228

Date

2018

Document Type

Thesis

Degree Name

Master of Science

Major

Earth Sciences

Concentration

Geophysics

Committee Chair

Chris Harold Cramer

Committee Member

Eric Guido Daub

Committee Member

Christine A. Powell

Abstract

The increase of statewide station coverage of Alaska since 2014 due to the presence of the EarthScope USArray (TA) stations provides an unprecedented opportunity to investigate crustal attenuation in Alaska using Lg-waves. This study determines Lg-wave attenuation and its spatial variations in Alaska using 187 local and regional crustal earthquakes that occurred between June 2014 and April 2018 in Alaska withML> 4.0. An inversion is performed over ten distinct passbands 1.0 Hz, 1.3 Hz, 2.0 Hz, 3.0 Hz, 4.0 Hz, 6.0 Hz, 8.0 Hz, 10.0 Hz, 13.0 Hz, and 16.0 Hz for all waveforms with a signal-to-noise ratio greater than 2. The regression yielded the functionQ(f) = 217(±28)f0.84(±0.04)(1.0≤f≤10.0Hz) which represents Alaska’s frequency-dependent attenuation. Alaska displays lowQ0and high frequency-dependence (η) which is indicative of a tectonically active region; but not as low as California or most of the Western United States.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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