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 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 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 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 Numerical Simulation of Earthquake Ground Motions in the Upper Mississippi Embayment written by J. Alfredo Fernandez Leon and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquake ground motions are needed to evaluate the seismic performance of new and existing structures and facilities. In seismically active regions the strong ground motion recordings database is usually sufficiently large to physically constrain the earthquake estimation for seismic risk assessment. However, in areas of low seismicity rate, particularly in the Central and Eastern United States, the estimation of strong ground motions for a specified magnitude, distance, and site conditions represents a significant issue. The only available approach for ground motion estimation in this region is numerical simulation.

Download or read book Seismic Wave Attenuation in the Unconsolidated Sediments of the Upper Mississippi Embayment written by Chigozie Simeon Obikili and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The attenuation characteristics of P waves in the Upper Mississippi embayment were estimated using U.S. Geological Survey explosion data recorded by 17 Portable Array for Numerical Data Acquisition (PANDA) stations deployed in the New Madrid Seismic Zone. Seven explosive sources, ranging from 500-lbs to 1000-lbs, located west of the PANDA stations were used. Head waves with an apparent velocity of 6km/s and the large amplitude wave train with an apparent velocity of 1.8 to 2km/s are identified from the seismogram. They were interpreted as a P-wave refracted from the top of Pleozoic basement and reverberating P-waves trapped in the unconsolidated embayment sediments, respectively. The P wave quality factor (Qp) of the unconsolidated sediments and the top of Paleozoic basement were estimated by taking the spectral ratio of coherent phases between two stations with similar azimuths from the source. A total of 21 station pairs were identified for spectral ratio analysis. The Qp values estimated were assumed to be frequency independent. The estimated Qp ranges from 113 to 280 for the embayment sediments. The mean Qp for the refracted phase is 290. Results show a lateral variation of the estimated Qp for the embayment sediments. Results are consistent with a previous study by Langston et al. (2005) which reported an average Qp2̃00 in the unconsolidated embayment sediments.

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 Magnetic Basement in the Upper Mississippi Embayment Region written by T. G. Hildenbrand and published by . This book was released on 1982 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Earthquake Information Bulletin written by and published by . This book was released on 1990 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 National Earthquake Hazards Reduction Program written by and published by . This book was released on 1985 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book National Earthquake Hazards Reduction Program Summaries of Technical Reports Volume XXVI written by and published by . This book was released on 1988 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book State of the Art Assessing Earthquake Hazards in the United States written by E. L. Krinitzsky and published by . This book was released on 1974 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Earthquakes of engineering interest are normally considered to result only from slippage or movement along existing faults. Hence, the detection of existing faults and their assessment as active or inactive constitutes an essential aspect of earthquake design. Some faults in soft sediments, through active, may not have the capability of generating earthquakes and must be so interpreted. Active faults generally may be evaluated for their maximum capacity to generate earthquakes through a synthesis of the local geologic and seismic history and worldwide relationships between fault dimensions earthquakes. Major earthquakes are caused by slippage along large faults, which are unlikely to be missed in detailed geologic investigations for sites in western United States. This may not be the case in the central and eastern United States. Small faults may be missed in any investigation so that a floating earthquake of limited size must be assumed to account for them. When faulting is not manifest at the surface, seismic history and geologic investigations can define geographic limits or zones for which floating earthquakes of various sizes are assigned"--Page ix.

Download or read book Heat Flow in the Upper Mississippi Embayment written by Chandler A. Swanberg and published by . This book was released on 1982 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book National Earthquake Hazards Reduction Program Summaries of Technical Reports Volume XXIX written by Geological Survey (U.S.) and published by . This book was released on 1989 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Earthquake Hazards Reduction Program written by and published by . This book was released on 1981 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: