Download or read book ANALYSIS FOR SOURCE SPECTRA ATTENUATION AND SITE EFFECTS FROM CENTRAL AND EASTERN UNITED STATES EARTHQUAKES NUREG CR 6564 U S NUCLEAR REGULATORY Commission written by and published by . This book was released on 1999* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Source Spectra Attenuation and Site Effects from Central and Eastern United States Earthquakes written by and published by . This book was released on 1998 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the results from three studies of source spectra, attenuation, and site effects of central and eastern United States earthquakes. In the first study source parameter estimates taken from 27 previous studies were combined to test the assumption that the earthquake stress drop is roughly a constant, independent of earthquake size. 200 estimates of stress drop and seismic moment from eastern North American earthquakes were combined. It was found that the estimated stress drop from the 27 studies increases approximately as the square-root of the seismic moment, from about 3 bars at 102° dyne-cm to 690 bars at 1025 dyne-cm. These results do not support the assumption of a constant stress drop when estimating ground motion parameters from eastern North American earthquakes. In the second study, broadband seismograms recorded by the United States National Seismograph Network and cooperating stations have been analysed to determine Q{sub Lg} as a function of frequency in five regions: the northeastern US, southeastern US, central US, northern Basin and Range, and California and western Nevada. In the third study, using spectral analysis, estimates have been made for the anelastic attenuation of four regional phases, and estimates have been made for the source parameters of 27 earthquakes, including the M{sub b} 5.6, 14 April, 1995, West Texas earthquake.

Download or read book Lg Excitation Attenuation and Source Spectral Scaling in Central and Eastern North America written by B. J. Mitchell and published by . This book was released on 1997 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of the PSHA Results of the 1993 EUS Update and the 1998 TIP Studies for Waste Bar written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From 1981 to 1989, Lawrence Livermore National Laboratory (LLNL) developed for the Nuclear Regulatory Commission a method for performing Probabilistic Seismic Hazard Analysis (PSHA) in the eastern US with results documented in NUREG/CR-5250. Improvements in the handling of the uncertainties lead to updated results documented in the 1993-EUS-Update study (NUREG-1488.) These results presented substantial differences with the utilities sponsored study performed by the Electric Power Research Institute (EPRI, 1989.) In order to understand the differences between the two studies, the Nuclear Regulatory Commission (NRC), the Department Of Energy (DOE) and EPRI jointly sponsored a study led by the Senior Seismic Hazard Analysis Committee (SSHAC) the task of which was to explain the differences between the two studies and provide guidance on how to perform a state-of-the-art PSHA. The work and conclusions of the SSHAC are documented in NUREG/CR-6372, 1997. As a follow-up to the 1997 SSHAC study, the Trial Implementation Project (TIP), (UCRL-ID-133494, 1998, NUREG/CR-6607) made use of the SSHAC recommendations and developed a set of more detailed guidance for performing PSHA. The TIP project tested the more complicated issue of development of the seismic zonation and seismicity models on two sites: Watts Bar and Vogtle. It was found that the uncertainty generated by artificial disagreements among experts can be considerably reduced through interaction and discussion of the available data and by identifying the elements common to all experts' interpretation. By concentration on those elements, it was possible to develop a consensus of the group on the way to characterize them and eliminate large unnecessary differences. The present study compares the results of the 1993-EUS-Update and the 1998-TIP studies and identifies the reasons for the differences, which were found to be: (1) Differences in the ground motion (GM) attenuation models; (2) The introduction of the Eastern Tennessee Seismic Zone (ETSZ) in the TIP study. We found that these two factors accounted for factor of 6 difference in mean estimates PGA hazard at high GM levels. The agreement between the two studies improved at lower PGA values. The results were in better agreement and only differed by about a factor of two at high ground motion levels, when the same GM model was used with each seismicity model. Finally, it was found that the composite rate of earthquakes around the Watts Bar site was about a factor of two higher for the TIP composite seismicity model than for the composite 1993-EUS-Update seismicity model.

Download or read book Central and Eastern United States Seismic Source Characterization for Nuclear Facilities written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Central and Eastern United States Seismic Source Characterization for Nuclear Facilities electronic Resource written by Kevin J.; United States. Nuclear Regulatory Commission; United States. Department of Energy; Electric Power Research Institute Coppersmith and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Effects from a High Yield Nuclear Cratering Experiment in Desert Alluvium written by W. V. Mickey and published by . This book was released on 1963 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: SEDAN was a thermonuclear cratering experiment with a yield of about 100 kt detonated at a depth of 660 feet and resulting in a crater of maximum apparent depth of 320 feet and average apparent diameter of about 1200 feet. About 7.5 million cubic yards of earth and rock were displaced. Transitory earth particle motions were on an average twice as large from stations on deep alluvial deposits compared to those on shallow deposits at the same distance. Computed seismic energy was about 2.45 x 10 to the 18th power ergs, equivalent to a local earthquake magnitude of 4.75. This indicates that 0.06 percent of the total source energy was converted to seismic energy. Frequency analysis revealed spectral peaks near 1 cps. (Author).

Download or read book Propagation and Excitation of Lg Sn and P Pn Waves from Eastern United States Earthquakes by Regression Analysis of RSTN Data Seismic Attenuation Studies at United Kingdom Arrays written by John H. Goncz and published by . This book was released on 1987 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: By applying regression analysis to amplitudes of the regional phases, pn, sn and lg in various frequency ranges we have derived the attenuation rates, extrapolated source spectra, and relative site responses for these phases in eastern north america using RSTN data. Observed regional phase amplitudes are modeled with three parameters. The estimates source excitation levels for all three phases exhibit high-frequency falloff rates between 1/f-sq-2 and 1/f-cubed -3 and have approximately the same shape. The average day and night noise levels of the RSTN stations were also measured as part of this study. The seismic noise displacement amplitude falls off roughly as 1/f-sq-2 over the frequency band from 1 TO 20 hz. A diurnal variation in the noise levels is observied at all of the RSTN sites, with the daytime noise averaging from 1.5 to 3 times higher than the nighttime noise. 2). the productivity of any future U.S. researchers using Blacknest data and of the Blacknest staff themselves will be significantly enhanced if the interactive graphics capability of the sun workstation were used for the analysis of seismic array data. It was therefore decided that the objective of this task would be to devise data base display and analysis software that could be used on the sun workstation at Blacknest. in particular, software would be installed that would make the Blacknest data accessible by programs already written to handle data.

Download or read book INVESTIGATION SEISMOTECTONICS IN THE EASTERN UNITED STATES USING A GEOGRAPHIC INFORMATION SYSTEM NUREG CR 6573 U S NUCLEAR REGULATORY COMMISSION written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1999* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scaling for Seismic Source Spectra and Energy Attenuation in the Chelan Region Eastern Washington written by Sheng-sheang Bor and published by . This book was released on 1977 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Source Spectra Moment and Energy for Recent Eastern Mediterranean Earthquakes written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past several years there have been several large (M{sub w}> 7.0) earthquakes in the eastern Mediterranean region (Gulf of Aqaba, Racha, Adana, etc.), many of which have had aftershock deployments by local seismological organizations. In addition to providing ground truth data (GT “5 km) that is used in regional location calibration and validation, the waveform data can be used to aid in calibrating regional magnitudes, seismic discriminants, and velocity structure. For small regional events (m{sub b} “4.5), a stable, accurate magnitude is essential in the development of realistic detection threshold curves, proper magnitude and distance amplitude correction processing, formation of an M{sub s}:m{sub b} discriminant, and accurate yield determination of clandestine nuclear explosions. Our approach provides a stable source spectra from which M{sub w} and m{sub b} can be obtained without regional magnitude biases. Once calibration corrections are obtained for earthquakes, the coda-derived source spectra exhibit strong depth-dependent spectral peaking when the same corrections are applied to explosions at the Nevada Test Site (Mayeda and Walter, 1996), chemical explosions in the recent ''Depth of Burial'' experiment in Kazahkstan (Myers et al., 1999), and the recent nuclear test in India. For events in the western U.S. we found that total seismic energy, E, scales as M{sub o}{sup 0.25} resulting in more radiated energy than would be expected under the assumptions of constant stress-drop scaling. Preliminary results for events in the Middle East region also show this behavior, which appears to be the result of intermediate spectra fall-off (f{sup 1.5}) for frequencies ranging between (almost equal to)0.1 and 0.8 Hz for the larger events. We developed a Seismic Analysis Code (SAC) coda processing command that reads in an ASCII flat file that contains calibration information specific for a station and surrounding region, then outputs a coda-derived source spectra, moment estimate, and energy estimate.

Download or read book Seismic Hazard Analysis Volume 5 Review Panel Ground Motion Panel and Feedback Results written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Site Specific Spectra Project (SSSP) was a multi-year study funded by the US Nuclear Regulatory Commission to provide estimates of the seismic hazards at a number of nuclear power plant sites in the Eastern US. A key element of our approach was the Peer Review Panel, which we formed in order to ensure that our use of expert opinion was reasonable. We discuss the Peer Review Panel results and provide the complete text of each member's report. In order to improve the ground motion model, an Eastern US Ground Motion Model Panel was formed. In Section 4 we tabulate the responses from the panel members to our feedback questionnaire and discuss the implications of changes introduced by them. We conclude that the net difference in seismic hazard values from those presented in Volume 4 is small and does not warrant a reanalysis. 22 figs.

Download or read book Application of Bounding Spectra to Seismic Design of Piping Based on the Performance of Above Ground Piping in Power Plants Subjected to Strong Motion Earthquakes NUREG CR 6240 written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Earthquake Source Spectra and Attenuation in Southeastern Canada written by Gail Marie Atkinson and published by . This book was released on 1993 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimating Absolute Site Effects written by and published by . This book was released on 2004 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors use previously determined direct-wave attenuation functions as well as stable, coda-derived source excitation spectra to isolate the absolute S-wave site effect for the horizontal and vertical components of weak ground motion. They used selected stations in the seismic network of the eastern Alps, and find the following: (1) all ''hard rock'' sites exhibited deamplification phenomena due to absorption at frequencies ranging between 0.5 and 12 Hz (the available bandwidth), on both the horizontal and vertical components; (2) ''hard rock'' site transfer functions showed large variability at high-frequency; (3) vertical-motion site transfer functions show strong frequency-dependence, and (4) H/V spectral ratios do not reproduce the characteristics of the true horizontal site transfer functions; (5) traditional, relative site terms obtained by using reference ''rock sites'' can be misleading in inferring the behaviors of true site transfer functions, since most rock sites have non-flat responses due to shallow heterogeneities resulting from varying degrees of weathering. They also use their stable source spectra to estimate total radiated seismic energy and compare against previous results. they find that the earthquakes in this region exhibit non-constant dynamic stress drop scaling which gives further support for a fundamental difference in rupture dynamics between small and large earthquakes. To correct the vertical and horizontal S-wave spectra for attenuation, they used detailed regional attenuation functions derived by Malagnini et al. (2002) who determined frequency-dependent geometrical spreading and Q for the region. These corrections account for the gross path effects (i.e., all distance-dependent effects), although the source and site effects are still present in the distance-corrected spectra. The main goal of this study is to isolate the absolute site effect (as a function of frequency) by removing the source spectrum (moment-rate spectrum) from the distance-corrected S-wave spectra. Typically, removing the S-wave source spectrum is difficult because of inadequate corrections for the source radiation pattern, directivity and random interference. In addition to complexities near the source, 2-D and 3-D structure beneath the recording site will result in an azimuth-dependent site effect. Since the direct wave only samples a narrow range in take-off and back-azimuth angles, multi-station averaging is needed to minimize the inherent scatter. To minimize these complicating effects, they apply the coda methodology outlined by Mayeda et al., (2003) to obtain stable moment-rate spectra. This methodology provides source amplitude and derived source spectra that are a factor of 3-to-4 times more stable than those derived from direct waves. Since the coda is commonly thought of as scattered energy that samples all ray parameters and back-azimuths, it is not very sensitive to the source radiation pattern and 3-D structure. This property makes it an excellent choice for use in obtaining average properties of the source, site and path effects in a region. Due to the characteristics of the techniques used in this study, all the inverted quantities are azimuthally averaged, since the aximuthal information is lost in the processing.

Download or read book Recommendations For Probabilistic Seismic Hazard Analysis NUREG CR 6372 Vol 1 U S Nuclear Regulatory Commission 1997 written by and published by . This book was released on 1997* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Regional Body Wave Attenuation Using a Coda Source Normalization Method written by and published by . This book was released on 2007 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: We develop a new methodology to determine apparent attenuation for the regional seismic phases Pn, Pg, Sn, and Lg using coda-derived source spectra. The local-to-regional coda methodology (Mayeda, 1993; Mayeda and Walter, 1996; Mayeda et al., 2003) is a very stable way to obtain source spectra from sparse networks using as few as one station, even if direct waves are clipped. We develop a two-step process to isolate the frequency-dependent Q. First, we correct the observed direct wave amplitudes for an assumed geometrical spreading. Next, an apparent Q, combining path and site attenuation, is determined from the difference between the spreading-corrected amplitude and the independently determined source spectra derived from the coda methodology. We apply the technique to 50 earthquakes with magnitudes greater than 4.0 in central Italy as recorded by MEDNET broadband stations around the Mediterranean at local-to-regional distances. This is an ideal test region due to its high attenuation, complex propagation, and availability of many moderate sized earthquakes. We find that a power law attenuation of the form Q(f) = Q0f{sup Y} fit all the phases quite well over the 0.5 to 8 Hz band. At most stations, the measured apparent Q values are quite repeatable from event to event. Finding the attenuation function in this manner guarantees a close match between inferred source spectra from direct waves and coda techniques. This is important if coda and direct wave amplitudes are to produce consistent seismic results.