Download or read book Mapping of Seismic Hazard Due to Shaking Including the Effect of Soil Conditions in the Mississippi Embayment written by Gabriel R. Toro and published by . This book was released on 1991* with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Seismic Hazard Mapping of the Mississippi Embayment Including the Effect of Soil Conditions written by Gabriel R. Toro and published by . This book was released on 1992 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Seismic Hazard Analysis of the Mississippi Embayment Incorporating Nonlinear Site Effects written by Mahesh Singh Dhar and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mississippi Embayment (ME) area is prone to damaging earthquakes as it lies over the New Madrid Seismic Zone, which is considered the most seismically active zone in the central and eastern United States. Several attempts have been made to account for the influence of deep sediment deposits of the ME on the propagation of seismic waves. This study presents the seismic and liquefaction hazards of the ME by adding the local geologic conditions to the 2014 USGS National Seismic Hazard Model. Both equivalent linear and nonlinear site response codes have been used to determine the amplification distribution at a site. This study uses the most up-to-date information available from different researchers and attempts to reduce the effect of uncertainties. A new 3D geologic model has been generated to assign geologic information and shear wave velocity to the soil profiles distributed over the ME area. The 3D model helps to generate an interpolated soil profile at a site for more accurate site response analysis, replacing the use of generic soil profiles. For liquefaction hazard analysis, updated surface geologic maps and liquefaction potential curves have been used. At short periods corresponding to peak ground acceleration the results show that seismic hazard is reduced on the lowlands in comparison to USGS results, mainly due to deamplification of ground motions from strong nonlinearity in the softer soil deposits. The NOAH (nonlinear Iwan model) site response code shows slightly lower hazard on the lowland soils in comparison to those obtained from SHAKE91 (equivalent linear). At long periods, lowlands deposits amplify hazards more in comparison to corresponding USGS results, mainly due to much less soil nonlinearity at long periods. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowlands sediments and low in Pleistocene loess of the uplands. The young sediments and shallow groundwater table depth in lowlands contribute to higher liquefaction hazard. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion even at short periods. Therefore, pore pressure effects should be considered in seismic hazard analysis of the ME. .
Download or read book The Memphis Shelby County Tennessee seismic hazard maps written by and published by DIANE Publishing. This book was released on with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Site Effects Study in the Mississippi Embayment and Uncertainties Evaluation in Site Response Analysis written by Arash Yarahmadi and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The local site conditions have paramount influence on the characteristics of seismic ground shaking. There are several methods of investigating seismic site effects which can be classified into two major categories; common site-specific response analysis, and procedures that use solely earthquake time series like the Standard Spectral Ratio (SSR), and Horizontal to Vertical Ratio (HVSR) methods. In the SSR method, the spectral ratios of earthquake records at a certain station can be evaluated with respect to a reference station located on a nearby outcrop rock. In the first part of the dissertation, we use earthquake records to find reference stations and use that reference station to find the site amplifications at the target stations inside the Mississippi Embayment (ME). We found WHAR, W41B, and UALR seismic stations, which have reference stations characteristics, close to the ME using horizontal-to-vertical spectrum ratio (HVSR) method. Amplification factors are obtained for six target stations inside the ME using an inversion method with WHAR seismic station as the reference station. Thirty-five local and regional earthquakes in the New Madrid and Arkansas seismic zones are used to perform the inversion. The results show the fundamental frequencies of these stations are as low as 0.2 HZ to 1 HZ, which corresponds to the soft features of their local conditions. In the second part of this dissertation, we focus on finding uncertainties in the 1-D equivalent linear site response analysis (SRA). In SRA these uncertainties are accounted for by generating random cases of soil parameters. Choosing suitable randomization bounds can decrease the effects of the uncertainties in soil parameters on SRA results like predicted spectral accelerations. These bounds quantified by the coefficient of variation (COV), which can be defined for different soil parameters. Using Vertical seismometer arrays, we can compare predicted and observed surface ground motions. In this study we evaluate COVs for different parameters of the soil that are the main input parameters of equivalent linear SRA. Coefficients of variation which generate minimum root means square errors of the observed and predicted response spectra are obtained for different site classes..
Download or read book Seismological Research Letters written by and published by . This book was released on 2006 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liquefaction Potential in the Central Mississippi Valley written by Stephen F. Obermeier and published by . This book was released on 1988 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scenario Earthquakes for Saint Louis MO Memphis TN and Seismic Hazard Maps for the Central United States Region written by G. R. Toro and published by . This book was released on 2001 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 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 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 Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstract Journal in Earthquake Engineering written by and published by . This book was released on 1993 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Maps of Ground Motion Amplification Representing the 3D Effects of the Mississippi Embayment on Wave Propagation written by Chandan K. Saikia and published by . This book was released on 2004 with total page 44 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 ShakeMaps written by and published by . This book was released on 2000 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adventures Through Deep Time written by R. B. VanArsdale and published by Geological Society of America. This book was released on 2009 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the geologic history of the central Mississippi River Valley and the surrounding area from the Precambrian through the Holocene. Its focal point is the New Madrid seismic zone.
Download or read book Treatise on Seismicity and Velocity Structure of the Northern Mississippi Embayment written by Akramalsadat Mostafanejad and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismicity of the New Madrid seismic zone, velocity structure of the northern Mississippi Embayment and extent of lithospheric discontinuities have been investigated in this work. Spatial variations of seismic b-value in the NMSZ have been determined. A region of high b-value (b1̃.8) in the northern segment of the Reelfoot fault has been found which reflects higher frequency in the occurrence rate of small earthquakes. This is attributed to fault creep in a medium with high silica content, high pore fluid pressure and extensive velocity heterogeneity. In another study, power spectral ratios of horizontal to vertical (H/V) and vertical to horizontal (V/H) components of teleseismic P-waves recorded by broadband seismic stations inside the Mississippi embayment have been examined to produce a 3-D average velocity map of the sediments. Fundamental resonance frequencies for S-wave reverberations in the northern Mississippi Embayment are about 0.2 to 0.4 Hz. Detailed linear gradient velocity models for Vp and Vs have also been calculated using teleseismic vertical and radial transfer functions at 60 broadband stations inside the Mississippi embayment and simultaneously inverting for velocity parameters. This led to a detailed 3-D linear gradient Vp and Vs model of the sediments for the first time. P-wave velocity starts at about 1.0 km/s near the surface and increases with depth to 3.5 to 4 km/s in deeper parts of the embayment. S-wave velocities vary from 0.3km/s to 1.6 km/s in deeper sections to the southwest. This detailed velocity structure of the unconsolidated sediments is developed so that it could be used to downward continue the transfer functions to the depth of 5 km to remove the effects of observed amplification, reverberation and large P-S conversions that occurs at the sediment-bedrock interface. The resulting waveforms are depth migrated to image the lateral and vertical changes of major reflectors with depth. The Moho boundary is observed with high resolution at depths of 45 to 55 km in the study area.
