Publication Date


Document Type


First Advisor

Clements, John Robert

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Physics


Seismic waves; Earth--Mantle


The Q-depth relation in the earth's mantle has been estimated for short period P waves from a Southern Alaskan earthquake and a Novaya Zemlya nuclear explosion. The power spectra of P waves obtained from a network of 17 stations have been used to measure the effects of attenuation over the whole mantle. These power spectra were computed using the Maximum Likelihood Method (MLM). Estimating a Q model on the basis of power spectra ratios between these stations has been unsuccessful. However, an indirect method was successful in which the short- period t* (travel time/quality factor Q) from the stations is obtained and compared to the t* values from an existing Q model. The probable Q models obtained are consistent with a high-Q upper and middle mantle, and a low Q region near the core-mantle boundary. The short-period Q values are much higher than Q values at longer periods. The result of this investigation suggests that Q increases with frequency.


Bibliography: pages [74]-80.


vii, 80 pages




Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type