Download or read book Variations in the Seismic Quality Factor Q for the Mississippi Embayment Sediments Utilizing Spectral Analysis of Reflection Data written by Michael Wilson Towle and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Development of Shear Wave Velocity Profiles in the Deep Sediments of the Mississippi Embayment Using Surface Wave and Spectral Ratio Methods written by Jonathan Pqul Bailey and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The deep soils of the Mississippi Embayment in the central United States will have a significant influence on earthquake ground motions generated by the New Madrid Seismic Zone. The seismic properties of these soils, which extend to depths of over 1000 meters in some areas, are poorly characterized at depths below 60 to 100 meters. This study presents shear wave velocity (Vs) profiles determined from Spectral-Analysis-of-Surface-Waves (SASW) measurements performed at eleven sites in Arkansas, Tennessee, and Missouri. These measurements were performed using the low-frequency field vibrator developed as part of the NSF Network for Earthquake Engineering Simulation (NEES) program. Shear wave velocity profiles were developed to depths of approximately 220 meters at eleven sites located throughout the Mississippi Embayment. In addition to the SASW measurements, ambient noise measurements of horizontal and vertical ground motions were performed to estimate the average Vs over the full profile depth using the H/V spectral ratio method. The Vs profiles derived from the SASW measurements compared well with Vs reference profiles that have been developed for the Mississippi Embayment and used in recent site response studies of the region. The observed variability of the profiles was found to be in general agreement with past assumptions used for the deep soil and correlated with changes in soil lithology. Relationships between the soil formations and Vs were consistent with past studies and provided information to greater depths. Lastly the H/V spectral ratio measurements were successfully applied at each of the eleven sites, but appeared to overestimate the average Vs.
Download or read book General Geology of the Mississippi Embayment written by Elliott Morse Cushing and published by . This book was released on 1964 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book National Water Quality Assessment Program the Mississippi Embayment written by Michael J. Mallory and published by . This book was released on 1994 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismological Research Letters written by and published by . This book was released on 1987* with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Shallow Shear Wave Attenuation in the Mississippi Embayment Using Vertical Seismic Profiling Data written by Jiandang Ge and published by . This book was released on 2007* with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic reflection profiles in the northern Mississippi Embayment written by Robert Morrison Hamilton and published by . This book was released on 1979 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Suspended Sediment and Bed Material Studies on the Lower Mississippi River written by Lamont G. Robbins and published by . This book was released on 1977 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate purpose of sediment studies is to develop a workable knowledge of the basic principles controlling the transport of sediment in the Lower Mississippi River and to apply this knowledge toward effective and economical stabilization works for flood control and navigation. The more immediate purpose of this report, however, is to present the data that have been collected and analyzed to date (1929-1974) and to show what trends exist in the quantities and sizes of suspended and bed sediments for the Vicksburg District.
Download or read book Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1983 with total page 1452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Morphodynamics of the Mississippi River written by Colin R. Thorne and published by . This book was released on 2001 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Lower Mississippi River, extending from Cairo, Illinois to the Gulf of Mexico, annually transports approximately 170 million tonnes of sediment. Historically, the quantity and calibre of sediment derived from catchment erosion have been affected by changes in land-use and management. For example, soil erosion increased during the 19th and early 20th centuries due to settlement by Europeans and this may have elevated catchment sediment supply to the Mississippi River, while more recently the supply of sediment from tributaries is known to have decreased markedly as a result of river engineering and management. Specifically, the construction of large dams as part of the Mississippi River and Tributaries (MR & T) Project has trapped sediment that would otherwise have been supplied to the Mississippi, particularly by the Missouri River. Marked changes have also occurred in the extent of eroding bankline along the Mississippi and these must have reduced the input of sediment derived from this source. For example, during the last three decades, a sustained construction program of bank revetments and dikes has produced a stable alignment. Given these trends in sediment supply from catchment, tributary and bank sources, it is not surprising that most studies of sediment movement report a large decrease in measured sediment loads at selected monitoring stations along the Mississippi River over the last 50 years (Kesel, 1988; Dardeau and Causey, 1990). However, a case can be made that the bed material load must have increased since the 1940s. This argument is based on analysis of morphological changes observed along the river that have led to an overall increase in slope and available stream power, coupled with the fact that bed material sizes along the river have remained almost constant.
Download or read book Values of Qs in the Unconsolidated Sediments of the Mississippi Embayment written by Scott P. Stovall and published by . This book was released on 2005 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geotechnical Properties of Mississippi River Delta Sediments Utilizing in Situ Pressure Sampling Techniques written by Mark William Johns and published by . This book was released on 1985 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crustal Structure of the Northern Mississippi Embayment and Reelfoot Rift from Seismic Refraction reflection Profiling written by William James Braile and published by . This book was released on 1993 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geophysics Tectonics Abstracts written by and published by . This book was released on 1987 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Velocity and Q from Reflection Seismic Data written by Berkan G. Ecevitoglu and published by . This book was released on 1907 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground water quality data from the northern Mississippi embayment Arkansas Missouri Kentucky Tennessee and Mississippi written by J. V. Brahana and published by . This book was released on 1985 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Velocity and Q from Reflection Seismic Data written by Berkan G. Ecevitoglu and published by . This book was released on 1987 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
