Download or read book High resolution Upper Crustal P and S Velocity Structures in the Upper Mississippi Embayment written by Fuchun Gao and published by . This book was released on 1999 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Crustal Structure Study of the Northern Mississippi Embayment written by Geological Survey (U.S.) and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic Hazards of the Upper Mississippi Embayment written by Roy Burbank Van Arsdale and published by . This book was released on 1998 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Crustal Structure Study of the Mississippi Embayment written by C. Bradford Austin and published by . This book was released on 1978 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Crustal Structure Study of the North Mississippi Embayment written by C. B. Austin and published by . This book was released on 1982 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground motion amplification of soils in the upper Mississippi Embayment written by Salome M. Romero and published by . This book was released on 2001 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geology based Site Coefficients for the Upper Mississippi Embayment written by Jennifer M. Knapp and published by . This book was released on 2003 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic Hazards of the Upper Mississippi Embayment written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquakes are a major hazard in the middle Mississippi River valley of the upper Mississippi embayment. Microseismicity along the New Madrid seismic zone is illuminating faults that are believed responsible for the great New Madrid earthquakes of 1811-1812. These faults are right lateral strike slip faults within the Blytheville arch and western margin of the Reelfoot rift that are linked by the southwest dipping Reelfoot reverse fault. The Bootheel lineament and back thrusts of the Reelfoot fault may also have slipped in 1811-12. Geomorphic effects of the 1811-12 sequence include displacement of the Mississippi River; uplift of the Lake County uplift, Tiptonville dome, Blytheville arch; subsidence of Reelfoot Lake, Big Lake, and Lake St Francis; landslides on the eastern bluffs of the Mississippi River valley; and extensive liquefaction. In addition there is evidence for 1811-12 landsliding on the eastern margin of Crowley's Ridge, formation of a lake on the Obion River, and formation of seismic craters on the loess covered eastern Mississippi Valley bluffs. Peripheral to the New Madrid seismic zone; the Big Creek, Commerce, and Crittenden County faults have Holocene displacement and faults along the margins of Crowley's Ridge have Pleistocene displacement. The margins of Sikeston Ridge are underlain by faults that apparently lifted the ridge in Quaternary time. Similarly, the eastern Mississippi Valley bluffs are underlain by faults that appear to have affected the current position of the Mississippi River. Thus, there is evidence for widespread Quaternary faulting within the upper Mississippi embayment Paleoliquefaction and trench excavations across the Reelfoot fault reveal a minimum of 3 prehistoric earthquakes and an estimated recurrence interval of 450 years.
Download or read book Study of Crustal Structure in the Middle Mississippi Embayment Using Long period Synthetic Seismogran Techniques written by Stephen I. Brewer and published by . This book was released on 1986 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Location And Characteristic Features of the Quaternary Deformation in the Mississippi Embayment from High resolution Seismic Reflection Data written by Lei Guo and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The New Madrid Seismic Zone (NMSZ), central US. is a controversial midcontinental region where the occurrence of large magnitude historical and prehistorical earthquakes and the high level of instrumental seismicity, clash with the lack of evident surface and subsurface deformation and with slow geodetic rates. To unravel this apparent paradox locally and to contribute to the understanding of intraplate seismicity globally, I integrate new high-resolution seismic reflection data acquired as part of the Mississippi River Project, data acquired for the Meeman-Shelby Fault study, and existing seismic reflection data, to investigate the long-term deformation in the northern Mississippi Embayment. In particular this study focuses on the identification and characterization of the structures where Quaternary deformation is accommodated in the northern Mississippi Embayment, on the comparison of the newly discovered structures with those that are seismically active today, and on the analysis of the distribution of the Quaternary deformation with respect to the NMSZ. The results show that Quaternary deformation has been accommodated along adjacent faults additional to the NMSZ fault system, and that the NMSZ faults are virtually undistinguishable from quiescent faults, except for the instrumental seismicity. The distribution of Quaternary deformation extends beyond the footprint of the high-velocity lower crustal layer (i.e. & ldquo;mafic rift pillow & rdquo;), invoked by several geodynamic models as the possible feature capable of concentrating stress in this region and responsible for the seismicity in the central US. The long-term Quaternary deformation appears to be accommodated along pre-existing features predominantly associated with the Reelfoot Rift structure.
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 A Baseline for Upper Crustal Velocity Variations Along the East Pacific Rise written by Mary Elizabeth Kappus and published by . This book was released on 1991 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book P and S Wave Velocity Structure of the Crust and Upper Mantle Under China and Surrounding Areas From Body and Surface Wave Tomography written by and published by . This book was released on 2008 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have used a combination of travel-time and surface wave tomography to obtain compressional and shear wave velocity distributions in the crust and upper mantle under China and surrounding areas. We first determined 3-D P- and S-wave velocity structures for the crust and uppermost mantle using local and regional arrival time data. Travel-time data from the Annual Bulletin of Chinese Earthquakes (ABCE) and the International Seismological Centre (ISC/EHB) were used. We then extended the model deeper into the mantle through the upper mantle transition zone using ISC/EHB data for P and PP phases combined with the ABCE data. We also used surface wave data from broadband stations to determine the S-velocity structure. Multi-mode surface wave tomography was employed for the whole region of China and surrounding areas and ambient noise interferometry was used in Tibet.
Download or read book Lithospheric Layering and Thickness Beneath the Contiguous United States written by Lin Liu and published by . This book was released on 2018 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Upper Mississippi Embayment (UME), where the seismically active New Madrid Seismic Zone resides, experienced two phases of subsidence commencing in the Late Precambrian and Cretaceous, respectively. To provide new constraints on models proposed for the mechanisms responsible for the subsidence, we computed and stacked P-to-S receiver functions recorded by 49 USArray and other seismic stations located in the UME and the adjacent Ozark Uplift and modeled Bouguer gravity anomaly data. The inferred thickness, density, and Vp/Vs of the upper and lower crustal layers suggest that the UME is characterized by a mafic and high-density upper crustal layer of ∼30 km thickness, which is underlain by a higher-density lower crustal layer of up to ∼15 km. Those measurements were the consequence of the passage of a previously proposed thermal plume. The thermoelastic effects of the plume would have induced wide-spread intrusion of mafic mantle material into the weak UME crust fractured by Precambrian rifting and increased its density, resulting in renewed subsidence after the thermal source was removed. In addition, to image upper mantle seismic discontinuities beneath the contiguous United States, a total of 284,121 S-to-P receiver functions (SRFs) recorded by 3,594 broadband seismic stations in the EarthScope Transportable Array and other permanent and temporary deployments are stacked in circular bins of 2° in radius. A robust negative arrival, representing a sharp discontinuity of velocity reduction with depth, is visible in virtually all the stacked traces in the depth range of 30-110 km"--Abstract, page iv.
Download or read book Crustal Structure in Areas of Active Crustal Accretion written by Leonard Dale Bibee and published by . This book was released on 1979 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Upper Mantle Structure of Western North America from Apparent Velocities of P Waves written by Mansour Niazi and published by . This book was released on 1965 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Variation of the compressional velocity with depth in the C-region of the upper mantle in western North America is studied. Apparent velocities of first arrivals across the Tonto Forest Array in Arizona were determined for about 70 shallow focus earthquakes. The epicenters range from 10 to 30 degrees in distance and are mostly south of the array. The method gives the slope of the travel time curve directly, the parameter required for a velocity-depth determination. For this distance range it is found that although the slope of the P travel time curve decreases substantially with distance, i.e., increasing apparent velocity, the variation is not uniform. Two relatively abrupt changes are observed at distances of about 17 and 24 degrees. These are most readily interpreted as two second order discontinuities in the region of the mantle above 1000 km. Assuming an average crustal structure as derived from seismic refraction measurements and taking the uppermost 200 km of the mantle given by Gutenberg or Jeffreys, various possibilities are explored for the form of variation of the P wave velocity with depth. The discontinuities in the rate of change of velocity with depth which cause the observed breaks in the apparent velocity curve are found to be at depths of about 320 and 640 km. Although no absolute times are required in the method the travel times for the various derived models are computed and compared with standard tables. (Author).
Download or read book The Velocity Structure of the Crust and Upper Mantle Under China from Broadband P and PP Waveform Analysis written by Joseph Beckers and published by . This book was released on 1994 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
