Date of Award
Master of Science
M. Beatrice Magnani
Charles A. Langston
A natural log spectral ratio technique is used to calculate Qp for the post-Paleozoic, unconsolidated sediments of the northern Mississippi Embayment. The method is applied to high-resolution marine seismic reflection data acquired along the Mississippi River. The method assumes a frequency independent Q over a certain frequency band. The frequency bands inspected range from 10-150 Hz and 10-200 Hz based on observed linear trends in the spectral ratio data. The large volume of data available allows for increased accuracy in Q estimates. Values of Qs are then approximated using an empirical Qp/Qs relationship for the embayment. Results show that average Qp=100-160 and average Qs=50-80. These values are nearly twice those calculated in previous studies, therefore suggesting that attenuation within the unconsolidated sediment column may not cancel out site amplification effects. These effects have important implications for seismic hazards and ground displacement predictions in the Central U.S. region.
Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Towle, Michael Wilson, "Variations in the Seismic Quality Factor Q for the Mississippi Embayment Sediments Utilizing Spectral Analysis of Reflection Data" (2010). Electronic Theses and Dissertations. 119.