Download or read book Characterizations of Linear Ground Motion Site Response in the New Madrid and Wabash Valley Seismic Zones and Seismicity in the Northern Eastern Tennessee Seismic Zone and Rome Trough Eastern Kentucky written by Nicholas von Seth Carpenter and published by . This book was released on 2019 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground Motion and Seismic Site Amplification in Central and Eastern North America and Regional Subduction Zones written by Grace Alexandra Parker and published by . This book was released on 2018 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ground motion intensity measures are used to represent various components of earthquake shaking intensity and frequency content in the form of simple parameters; examples include peak ground acceleration, Arias intensity, and pseudo-spectral acceleration (PSA). Ground motion models (GMMs) are developed to predict these intensity measures as a function of earthquake source, wave propagation path, and local geotechnical site conditions. GMMs are formulated to capture the underlying physics of source processes, wave propagation, and site response, with individual model parameters set based on various combinations of empirical ground motion data analysis and physics-based ground motion simulations. The majority of GMMs are conditioned for hard rock reference sites, with shear wave velocity (VS) = 3000 m/s, or with a time-averaged shear wave velocity in the upper 30 meters of the crust (VS30) = 760 m/s. Additional site amplification models are necessary in order to estimate GMIMs for other site conditions, including weathered rock and soil sites. As shear waves propagate vertically in the near-surface, the conservation of energy dictates that the wave amplitude must increase as the seismic velocity of the medium decreases. This amplification, or the so-called linear site effect, is usually parameterized using VS30, and sometimes site fundamental frequency or depth to bedrock, if available. This thesis has two parts, according to subject matter. The first part of this thesis, consisting of Chapters 2, 3, and 4, focuses on seismic site characterization and site amplification in central and eastern North America (CENA) in the context of the Next Generation Attenuation-East (NGA-East) project. Chapter 2 presents a hybrid geology-slope approach for VS30 estimation that utilized a new and expanded shear-wave velocity (VS) measurement database for CENA. The proxy is conditioned on geologic category from newly considered large-scale geologic maps, the extent of Wisconsin glaciation, sedimentary basin structure, and 30 arc-sec topographic gradient. Nonglaciated sites were found to have a modest natural log dispersion of VS30 ( ln V= 0.36) relative to glaciated sites ( lnV = 0.66), indicating better predictability of VS30 for the former. These findings were used estimate the mean and standard deviation of VS30 for NGA-East recording stations when measurements were not available. Chapter 3 presents empirical linear site amplification models conditioned on time-averaged shear wave velocity in the upper 30 m (VS30) for CENA, developed using a combination of least-squares, mixed effects, and Bayesian techniques. Site amplification is found to scale with VS30 for intermediate to stiff site conditions (VS30 > 300 m/s) in a weaker manner than for active tectonic regions. For stiff sites (> 800 m/s), I find differences in amplification for previously glaciated and non-glaciated regions, with non-glaciated sites having lower amplification. The models account for predictor uncertainty, which does not affect the median model, but decreases model dispersion. Lastly, Chapter 4 presents recommendations for modeling of ergodic site amplification in CENA, based primarily on results from the literature (including the model in Chapter 3), for application in the U.S. Geological Survey national seismic hazard maps. Previously, the maps have used site factors developed using data and simulations for active tectonic regions; however, results from NGA-East demonstrate different levels of site amplification in CENA. The recommended model has three terms, two of which describe linear site amplification: an empirically constrained VS30-scaling term relative to a 760 m/s reference, and a simulation-based term to adjust site amplification from the 760 m/s to the CENA reference of VS = 3000 m/s. The second part of this thesis, consisting of Chapters 5 and 6, focuses on the development of a global GMM and site amplification model with regional adjustment factors for subduction zone regions as a part of the Next Generation Attenuation-Subduction (NGA-Sub) project. Chapter 5 presents global subduction zone GMMs for interface and intraslab events, with regionalized terms for Alaska, Cascadia, Central America. Mexico, Japan, South America, and Taiwan. The near-source saturation model, magnitude-dependent geometrical spreading, and magnitude-scaling break point are constrained using simulations and fault geometry, and the anelastic attenuation, magnitude scaling, and depth scaling terms are constrained empirically. The model is regionalized in the constant, anelastic attenuation, and depth-scaling terms, and the magnitude break-point. When applying the model to a region not considered in the study, we recommend using an appropriate range of epistemic uncertainty that captures regional variation. Chapter 6 presents a subduction-specific site amplification model, meant to be paired with the reference-rock GMM of Chapter 5. This site amplification model for subduction regions accounts for regional differences in VS30-scaling, and re-calibrates a widely used nonlinear site term for active tectonic regions.
Download or read book Ground Motion Prediction Equations for Central and Eastern North America CENA written by Arash Zandieh and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: First, a new path model, including the geometrical spreading and the quality factor functions, is developed for the New Madrid seismic zone (NMSZ) using recorded small and moderate earthquakes. The database consists of 500 broadband seismograms from 63 events of magnitude Mw 2.5 to 5.2. All the broadband stations are located within the Mississippi embayment. The vertical components of the records are processed and used to define the path effect term in the frequency range of 0.2 to 30 Hz. At distances less than 70 km, the spectral amplitudes decay as R-1; between 70 and 140 km, spectral amplitudes increase with distance and the geometric spreading is defined as R+0.25; beyond 140 km, the attenuation is described by R-0.5. The quality factor function is expressed as Q=614f0.32 for frequencies greater than 1 Hz.Second, the horizontal-to-vertical component (H/V) spectral ratio is used as an estimation of the site response in the NMSZ. The observed average H/V ratios suggest site amplification between 2 and 4 in the low-frequency range (f
Download or read book Estimated Ground Motions for a New Madrid Event written by and published by . This book was released on 1989 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground Motion Scaling from Earthquakes in the New Madrid Seismic Zone written by Robert B. Herrmann 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 Estimates of Strong Ground Motion in Shelby County Tennessee Resulting from Large Earthquakes in the New Madrid Seismic Zone written by Guang Yu and published by . This book was released on 1989 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic Ground Motions in Shelby County Tennessee Resulting from Large New Madrid Earthquakes written by Arch C. Johnston and published by . This book was released on 1988 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report Characterization of Ground Motions During the Northridge Earthquake of January 17 1994 written by Paul Sommerville and published by . This book was released on 1995 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Tomographic Analysis of the Wabash Valley Seismic Zone written by Bill Sweidan and published by . This book was released on 2021 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Wabash Valley Seismic Zone (WVSZ), or Wabash Valley Fault System (WVFS), is an intraplate region of higher-than-average seismicity located within the Illinois Basin. This region has produced three 5.0+ magnitude earthquakes within the last 50 years, and recent paleoseismological studies have also shown evidence for 7.0+ magnitude events occurring within the history of the fault system. The prominent faults within the system have very little surface expression, so available data of the orientation, trend, and extent of the fault system comes from seismic reflection data and are observed at depth within mine shafts throughout Illinois. The Wabash Valley faults are contained between the LaSalle Anticlinal Belt, a prominent Precambrian complex of en echelon folds to the north, and the junction of the east/west trending Cottage Grove and Rough Creek faults to the south. Most of the faults trend to the NE and can display vertical offsets into the hundreds of meters, penetrating the Precambrian basement rock at depth. Though there are some similarities in fault orientation and trend to the faults contained within the New Madrid Seismic Zone to the SE, the possible connection to and the tectonic setting of the Wabash Valley Seismic Zone is ambiguous. As part of the Earthscope project to map the crustal structure of the North American continent, data was passively collected along a 400-kilometer Flexible Array across Illinois and Indiana for the purpose of wide angle and deep seismic profiling in the form of tomography. Utilizing a new ray tracing methodology based on Dijkstra's algorithm, tomograms of the study area were created by inverting for Vp data collected from this array. Our tomograms show no evidence for a rift pillow system under the Wabash Valley as predicted, but there is evidence for a dipping fast anomalous zone that has been previously hypothesized from reprocessed COCORP data. We consider this COCORP reflector as an upper layer of eclogite above old, subducted crust with a higher impedance contrast than the surrounding mantle material. Further investigation is warranted, particularly with respect to ray directionality as rays arriving from north of the array do not travel through the fault system itself, whereas southern rays do. It is our hope that further studying including only southern ray paths may illuminate a supposed rift pillow system.
Download or read book Spatial Variation of Seismic Ground Motions written by Aspasia Zerva and published by CRC Press. This book was released on 2016-04-19 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spatial variation of seismic ground motions denotes the differences in the seismic time histories at various locations on the ground surface. This text focuses on the spatial variability of the motions that is caused by the propagation of the waveforms from the earthquake source through the earth strata to the ground surface, and it brings toge
Download or read book Probabilistic Estimates of Maximum Seismic Horizontal Ground Motion on Rock in Coastal California and the Adjacent Outer Continental Shelf written by and published by . This book was released on 1981 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Integrated Geological Geophysical and Geochemical Investigation of the Major Fractures on the East Side of the New Madrid Earthquake Zone written by Richard Gordon Stearns and published by . This book was released on 1987 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earthquake Scenario and Probabilistic Ground Shaking Maps for the Salt Lake City Utah Metropolitan Area written by Ivan Gynmun Wong and published by Utah Geological Survey. This book was released on 2002 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Salt Lake City metropolitan area is one of the most seismically hazardous urban areas in the interior of the western U.S. because of its location within the Intermountain Seismic Belt and its position adjacent to the active Wasatch fault. The elapsed time since the last large earthquake on the Salt Lake City segment of the Wasatch fault is approaching the mean recurrence interval based on the short-term paleoseismic record. In order to help raise the awareness of the general public and to help reduce earthquake risk in this area, we have developed nine microzonation maps showing surficial ground-shaking hazard. The maps are GIS-based and incorporate the site response effects of the unconsolidated sediments that underlie most of the metropolitan area within Salt Lake Valley. These nine maps, at a scale of 1:75,000, make up three sets, each consisting of three maps that display color-contoured ground motions in terms of (1) peak horizontal acceleration, (2) horizontal spectral acceleration at a period of 0.2 sec (5 Hz) and, (3) horizontal spectral acceleration at a period of 1.0 sec (1 Hz). One set of maps consists of deterministic or “scenario” maps for a moment magnitude (M) 7.0 earthquake on the Salt Lake City segment of the Wasatch fault. The two other sets are probabilistic maps for the two return periods of building code relevance, 500 and 2,500 years.
Download or read book Site specific Seismic Ground Motion Analyses for Transportation Infrastructure in the New Madrid Seismic Zone written by Brady Ray Cox and published by . This book was released on 2012 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summaries of Technical Reports Volume XIX written by and published by . This book was released on 1985 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground Motion Studies written by Weston Geophysical Research, Inc and published by . This book was released on 1976 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Simulated Ground Motion Peak Accelerations with the 2006 International Building Code Design Response Spectra for the New Madrid Seismic Zone written by Jodi Kostecki and published by . This book was released on 2008 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goal of this study is to compare the 2006 International Building Code design response spectrum to the single degree of freedom linear elastic response spectrum generated from synthetic earthquake ground motions. This is done by first producing a series of synthetic ground motion accelerations formulated from site parameters that are characteristic of the New Madrid Seismic Zone, and then filtering the acceleration data through a baseline correction scheme to adjust any drifts in the displacement response. Next, the response spectra of each time series is calculated and used to find the average spectral response for all of the acceleration traces. The amplitudes of this plot are compared to a 2006 International Building Code design response spectrum formulated for the same site conditions. In addition, the effects of stress drop and magnitude on the simulation response spectrum were examined. For this study, the simulated ground motions produced larger spectral response acceleration values for structures with larger natural periods as compared to the general method. This would imply that implementing the stochastic method for specific site study design in the New Madrid Seismic Zone would create larger design forces and thus, stronger structures, compared to the general method outlined in the 2006 IBC. It was also determined that an accurate estimation of moment magnitude and stress drop for the site is a key factor in stochastic ground motion simulation.
