Download or read book Determination of Shallow Shear Wave Velocity Structure and Attenuation in the Mississippi Embayment from VSP and Refraction Data written by Jiandang Ge and published by . This book was released on 2005 with total page 394 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 Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1988 with total page 1656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Velocity and Attenuation Structure of the Near Surface from Short Range Refraction Experiments in Western Tennessee written by Benjamin Gemballa and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-surface shear-wave velocity (Vs) profiles and anelastic coefficients for Rayleigh- and Love-waves have been determined for three sites in Eastern Dyer County using short-range reflection/refraction experiments that recorded both the vertical and transverse components of seismic waves. The upper 10 meters for all sites display Vs ranging between 70 and 242 m s-1. The largest value for VSV is at the Johnson-Newbern site where velocity increases to 1500 m s-1. The Pate site displays the highest VSH value at 800 m s-1. A predominately linear increas in velocity can be used to define this data. Average values of 5-50 for Qs explain the inability to complete seismic reflection profiling and may provide a new upper limit for attenuation in the shallow subsurface. The attenuation values and velocity profiles created as a result of this research should be considered in earthquake hazard assessments in the vicinity of the New Madrid Seismic Zone. .
Download or read book Shear wave Velocity Database and Derivative Mapping for the Upper Mississippi Embayment written by David M. Vance and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal written by Canadian Society of Exploration Geophysicists and published by . This book was released on 1990 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Cumulative Index Geophysics Journal of the Society of Exploration Geophysicists 1936 1988 Inclusive Early Geophysical Papers Geophysics the Leading Edge of Exploration selected Papers 1982 88 Inclusive written by William J. Zwart and published by . This book was released on 1990 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparative Analyses of Geophysical Methods for Determining Shear Wave Velocity of Soils written by Thanop Thitimakorn and published by . This book was released on 2006 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Missouri Department of Transportation (MoDOT) routinely acquires seismic cone penetrometer (SCPT) shear wave velocity control as part of the routine investigation of soils at highway structures or other geotechnical sites within the Mississippi Embayment. In an effort to ensure their geotechnical investigations are as effective and efficient as possible, the SCPT tool and several available alternatives (crosshole: CH; multichannel analysis of surface waves: MASW; and refraction microtremor: ReMi) were evaluated and compared on the basis of the interpretation of processed field data acquired at two test sites in the Poplar Bluff area, southeast Missouri. These four methods for determining the shear wave velocity of soils were subsequently ranked in terms of accuracy, functionality, cost effectiveness, other considerations and overall utility. On the basis of the comparative analyses, it is concluded that MASW data are generally more reliable than SCPT data, comparable to quality ReMi data and only slightly less accurate than CH data. However, MASW's other advantages generally make it a superior choice over the other methods for general soil classification purposes to depths of 100 ft. (as per NEHRP recommendations)"--Abstract, leaf iii.
Download or read book Study of Surface Wave Methods for Deep Shear Wave Velocity Profiling Applied in the Upper Mississippi Embayment written by Jianhua Li and published by . This book was released on 2008 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface wave methods have become an important tool for non-intrusively and inexpensively determining shear wave velocity (V [subscript-s]) profiles for many geotechnical earthquake engineering applications. The primary objectives of this study are to (1) compare active-source and passive (ambient vibration) surface wave methods for developing V [subscript-s] profiles to depths of 200 to 300 m at deep soil sites, and (2) identify the primary factors affecting the reliability and consistency of surface wave methods. This comparative study became possible with the advent of a unique low- frequency field vibrator developed as part of the National Science Foundation's (NSF) Network for Earthquake Engineering Simulation (NEES) program. This vibrator is able to actively excite surface wave energy down to frequencies of less than 1 Hz. Four surface wave methods (two active-source methods and two passive-source methods) were applied in this study, namely: (1) the Spectral-Analysis-of-Surface-Waves (SASW) method, (2) the active-source frequency- wavenumber ([function]-k) method, (3) the passive-source frequency-wavenumber ([function]-k) method and (4) the refraction microtremor (ReMi) method. The focus of this study is on two critical aspects of surface wave methods: (1) development of a reliable surface wave dispersion curve from field measurements, and (2) compatibility between the experimental dispersion curve and the theoretical model used in the inversion procedure to develop the final V [subscript-s] profile. Measurements were performed at eleven sites distributed over a distance of about 180 km in the upper Mississippi Embayment in the central United States, where soil deposits are hundreds of meters deep. Limitations associated with each of the four methods were identified in this study. With respect to the SASW method it was found that potential phase unwrapping problems could cause an erroneous estimate of the dispersion curve. These errors were found to be associated with an abrupt mode transition caused by a strong velocity contrast at a shallow depth. With respect to the active-source [function]-k approach, it was demonstrated that near-field effects caused by a short near- source offset produced an underprediction of the surface wave dispersion curve at long wavelengths. Recommendations for acceptable source offset distances were developed based on the results from this study. The performance of the passive approaches (passive [function]-k method and ReMi method) was shown to be strongly dependent on the local ambient wavefield characteristics. Results from a study of the ambient wavefield characteristics at the 11 sites showed high ambient vibration levels at all sites in the frequency range of 1 to 4 Hz. Passive measurements using a circular array provided good comparisons with the active-source methods out to wavelengths of 500 m (2.5 times the array aperture) in most cases. Poor performance at one site was shown to be due to a multi-source wavefield at low frequencies. An improved comparison at this site was achieved by applying high-resolution processing methods. The ReMi method was found to provide good results down to frequencies of 3 to 4 Hz (wavelengths of 100 to 150 m) but very poor performance at lower frequencies (
Download or read book Shear wave Velocities in Parkway Basin Wainuiomata from Refraction Microtremor Surface Wave Dispersion written by A. E. Kaiser and published by . This book was released on 2006 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Shear Wave Velocity Structure in the Rio Grande Rift Through Receiver Function and Surface Wave Analysis Appendix B written by and published by . This book was released on 1991 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Waveform modeling of radial component receiver functions from ANMO (Albuquerque, New Mexico Observatory) for three source back azimuths (northwest, southeast, and southwest) has been performed. The receiver functions were derived through source equalization deconvolution of merged long period and short period digital three component seismograms. Derived S-wave velocity models reflect dominantly intermediate composition granitic rock in the upper crust (above 15 km depth, Vs 3.5 km/sec) and middle crust (15-25 km depth, Vs 3.5-3.7 km/sec). Lower crustal shear velocities of approximately 3.75-3.85 km/sec may be representative of intermediate-to-mafic granulite facies, possibly together with previously underplated mafic material and other precursor crustal rocks. Shear wave attenuation between about 30-34 km may indicate a lower crustal partial melt zone. A 3-to-6 km thick interval is interpreted as a partial melt zone in the upper mantle leading into lessdepleted spinel peridotite (Vs = 4.25-4.35 km/ sec) near 37 km. Inversion of EPT-ALQ interstation dispersion data for average S-wave velocity structure produces a satisfactory velocity tie to the middle and lower crust portions of the southwest back azimuth model.
Download or read book Shear Velocity Structure in the Eastern United States from the Inversion of Surface Wave Group and Phase Velocities written by Brian J. Mitchell and published by . This book was released on 1979 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-station group velocities at periods between 4 and 70 seconds and single-station phase velocities at periods between 10 and 50 seconds are obtained for a broad region of the eastern United States for both Rayleigh and Love waves. These data were obtained by the single-station method using earthquakes with known fault-plane solutions in the central United States. The group velocity data are combined with earlier acquired attenuation data to yield Q values for Rayleigh and Love waves in the eastern United States. Inversions of the dispersion curves for shear-velocity models of the crust and upper mantle indicate that all of the data can be explained satisfactorily by a single model which is isotropic in its elastic properties. This model includes a surface layer of low-velocity sediments, and is characterized by upper crustal shear-wave velocities which increase from 3.4 to 3.7 km/sec with increasing depth, by lower crustal shear-wave velocities between 4.0 and 3.8 km/sec, and by an upper-most mantle shear-wave velocity of about 4.8 km/sec. The fundamental-mode data of this study do not require a low-velocity zone in either the crust or upper mantle. Higher-mode velocities and wave forms, although having potentially greater resolving power than the fundamental-mode data, were too inconsistent to contribute to the elucidation of detailed features of the crust-upper mantle model. (Author).
Download or read book Determination of Shear Wave Velocity Structure in the Rio Grande Rift Through Receiver Function and Surface Wave Analysis written by Brian P. Murphy and published by . This book was released on 1991 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shear Wave Velocity Determination Using Surface Wave Dispersion written by Mike E. Craven and published by . This book was released on 1992 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Detection of SH type Seismic Shear Waves by Means of Angular Accelerometers written by James H. Whitcomb and published by . This book was released on 1969 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method for detecting and recording seismic shear waves by means of angular accelerometers.
Download or read book Shear Wave Velocity Structure in the Earth from Differential Shear Wave Measurements written by Robert Allan Uhrhammer and published by . This book was released on 1977 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
