Download or read book Ground Motion and Variability from 3 D Deterministic Broadband Simulations written by Kyle Withers and published by . This book was released on 2016 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: The accuracy of earthquake source descriptions is a major limitation in high-frequency ($>1$ Hz) deterministic ground motion prediction, which is critical for performance-based design by building engineers. With the recent addition of realistic fault topography in 3D simulations of earthquake source models, ground motion can be deterministically calculated more realistically up to higher frequencies. We first introduce a technique to model frequency-dependent attenuation and compare its impact on strong ground motions recorded for the 2008 Chino Hills earthquake. Then, we model dynamic rupture propagation for both a generic strike-slip event and blind thrust scenario earthquakes matching the fault geometry of the 1994 Mw 6.7 Northridge earthquake along rough faults up to 8 Hz. We incorporate frequency-dependent attenuation via a power law above a reference frequency in the form $Q_0f^n$ ,with high accuracy down to Q values of 15, and include nonlinear effects via Drucker-Prager plasticity. We model the region surrounding the fault with and without small-scale medium complexity in both a 1D layered model characteristic of southern California rock and a 3D medium extracted from the SCEC CVMSi.426 including a near-surface geotechnical layer. We find that the spectral acceleration from our models are within 1-2 interevent standard deviations from recent ground motion prediction equations (GMPEs) and compare well with that of recordings from strong ground motion stations at both short and long periods. At periods shorter than 1 second, Q(f) is needed to match the decay of spectral acceleration seen in the GMPEs as a function of distance from the fault. We find that the similarity between the intraevent variability of our simulations and observations increases when small-scale heterogeneity and plasticity are included, extremely important as uncertainty in ground motion estimates dominates the overall uncertainty in seismic risk. In addition to GMPEs, we compare with simple proxy metrics to evaluate the performance of our deterministic models and to determine the importance of different complexities within our model. We find that 3D heterogeneity, at both the long and short scale-lengths, is necessary to agree with data, and should be included in future simulations to best model the ground motion from earthquakes.

Download or read book Quantification of Ground Motions by Broadband Simulations written by Katrin Kieling and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many procedures of seismic risk mitigation, ground motion simulations are needed to test systems or improve their effectiveness. For example they may be used to estimate the level of ground shaking caused by future earthquakes. Good physical models for ground motion simulation are also thought to be important for hazard assessment, as they could close gaps in the existing datasets. Since the observed ground motion in nature shows a certain variability, part of which cannot be explained by macroscopic parameters such as magnitude or position of an earthquake, it would be desirable that a good physical model is not only able to produce one single seismogram, but also to reveal this natural variability. In this thesis, I develop a method to model realistic ground motions in a way that is computationally simple to handle, permitting multiple scenario simulations. I focus on two aspects of ground motion modelling. First, I use deterministic wave propagation for the whole frequency range - from static deformation to approximately 10 Hz - but account for source variability by implementing self-similar slip distributions and rough fault interfaces. Second, I scale the source spectrum so that the modelled waveforms represent the correct radiated seismic energy. With this scaling I verify whether the energy magnitude is suitable as an explanatory variable, which characterises the amount of energy radiated at high frequencies - the advantage of the energy magnitude being that it can be deduced from observations, even in real-time. Applications of the developed method for the 2008 Wenchuan (China) earthquake, the 2003 Tokachi-Oki (Japan) earthquake and the 1994 Northridge (California, USA) earthquake show that the fine source discretisations combined with the small scale source variability ensure that high frequencies are satisfactorily introduced, justifying the deterministic wave propagation approach even at high frequencies. I demonstrate that the energy magnitude can be used to calibrate the high-frequency content in ground motion simulations. Because deterministic wave propagation is applied to the whole frequency range, the simulation method permits the quantification of the variability in ground motion due to parametric uncertainties in the source description. A large number of scenario simulations for an M=6 earthquake show that the roughness of the source as well as the distribution of fault dislocations have a minor effect on the simulated variability by diminishing directivity effects, while hypocenter location and rupture velocity more strongly influence the variability. The uncertainty in energy magnitude, however, leads to the largest differences of ground motion amplitude between different events, resulting in a variability which is larger than the one observed. For the presented approach, this dissertation shows (i) the verification of the computational correctness of the code, (ii) the ability to reproduce observed ground motions and (iii) the validation of the simulated ground motion variability. Those three steps are essential to evaluate the suitability of the method for means of seismic risk mitigation.

Download or read book Encyclopedia of Earthquake Engineering written by Michael Beer and published by Springer. This book was released on 2016-01-30 with total page 3953 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia of Earthquake Engineering is designed to be the authoritative and comprehensive reference covering all major aspects of the science of earthquake engineering, specifically focusing on the interaction between earthquakes and infrastructure. The encyclopedia comprises approximately 300 contributions. Since earthquake engineering deals with the interaction between earthquake disturbances and the built infrastructure, the emphasis is on basic design processes important to both non-specialists and engineers so that readers become suitably well informed without needing to deal with the details of specialist understanding. The encyclopedia’s content provides technically-inclined and informed readers about the ways in which earthquakes can affect our infrastructure and how engineers would go about designing against, mitigating and remediating these effects. The coverage ranges from buildings, foundations, underground construction, lifelines and bridges, roads, embankments and slopes. The encyclopedia also aims to provide cross-disciplinary and cross-domain information to domain-experts. This is the first single reference encyclopedia of this breadth and scope that brings together the science, engineering and technological aspects of earthquakes and structures.

Download or read book Best Practices in Physics based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations written by Luis A. Dalguer and published by Birkhäuser. This book was released on 2017-12-20 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects several extended articles from the first workshop on Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (BestPSHANI). Held in 2015, the workshop was organized by the IAEA to disseminate the use of physics-based fault-rupture models for ground motion prediction in seismic hazard assessments (SHA). The book also presents a number of new contributions on topics ranging from the seismological aspects of earthquake cycle simulations for source scaling evaluation, seismic source characterization, source inversion and physics-based ground motion modeling to engineering applications of simulated ground motion for the analysis of seismic response of structures. Further, it includes papers describing current practices for assessing seismic hazard in terms of nuclear safety in low seismicity areas, and proposals for physics-based hazard assessment for critical structures near large earthquakes. The papers validate and verify the models by comparing synthetic results with observed data and empirical models. The book is a valuable resource for scientists, engineers, students and practitioners involved in all aspects of SHA.

Download or read book Enhancement and Validation of Ground Motion Simulations written by Nan Wang and published by . This book was released on 2021 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of strong ground motion is central to seismic hazard analysis in order to estimate losses during major earthquakes. Ground motion simulations are essential to seismic ground motion prediction, especially for locations of infrequent observations, such as large magnitude and short distance events, where simulations can provide a viable alternative to data. Therefore, enhancement and validation of ground motion simulations, the primary goal of this dissertation, are highly desirable. In Chapter 2, we quantify the effects of four important factors on ground motions from large normal-faulting earthquakes on the Wasatch fault in the Salt Lake Basin: rupture direction, location on the hanging wall versus the footwall, deep 3D basin structure, and the distance from the rupture in the near field range. In Chapter 3, we attempt to validate the presence of several proposed waveguides in the Los Angeles area using 3D simulations and observed data from ambient noise. Here, we compare the numerical and empirical surface-to-surface Green tensors for virtual sources located on the San Andreas Fault. The regions of large peak motions caused by waveguide focusing in the simulations show generally good agreement with increases in the Green tensor amplitudes, supporting the presence of two separate waveguides in greater Los Angeles. In Chapters 4 and 5, we develop an empirical frequency-dependent spatial ground motion correlation model and methods to rectify simulation techniques that otherwise produce synthetic time histories deficient in inter-frequency and spatial correlation structure. The methods are tested using a hybrid deterministic-stochastic broadband ground motion generation module, where our method reproduces the empirical correlations well for a large number of realizations without biasing the fit of the median of the spectral accelerations to data. We find that the best fit of the inter-frequency correlation to data is obtained assuming that the horizontal components are correlated with a correlation coefficient of about 0.7.

Download or read book Ground Motion Simulations written by Lynne Schleiffarth Burks and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineers use earthquake ground motions for a variety of reasons, including seismic hazard assessment, calibration of ground motion prediction equations (GMPEs), and input to nonlinear response history analysis. These analyses require a significant number of ground motions and for some scenarios, such as earthquakes with large magnitudes and short distances, it may be difficult to obtain a sufficient number of ground motion recordings. When sufficient recordings do not exist, engineers modify available recordings using scaling or spectrum matching, or they use ground motion simulations. Ground motion simulations have existed for decades, but recent advances in simulation methods due to improved source characterization and wave propagation, coupled with increased computing power, have increased potential benefits for engineers. But before simulations can be used in engineering applications, simulations must be accessible and consistent with natural observations. This dissertation contributes to the latter issue, and it investigates the application of simulations to specific engineering problems. The Southern California Earthquake Center (SCEC) Broadband Platform (BBP) is an open-source software distribution that enables third-party users to simulate ground motions using research code contributed by model developers. Because the BBP allows users to compute their own simulations with little knowledge of the underlying implementation and it ensures that all calculations are reproducible, it is extremely valuable for simulation validation and engineering applications. In this dissertation, the BBP is evaluated as a simulation generation tool from an engineering perspective. Ground motions are simulated to study parameters of engineering interest, such as high-frequency variability, near-fault ground motions, and local site response. Though some parameters need further development, such as site response (which is currently implemented using simple empirical amplification), the BBP proves to be an effective tool for facilitating these types of engineering studies. This dissertation proposes a simulation validation framework based on simple and robust proxies for the response of more complicated structures. We compile a list of proxies with robust empirical models that are insensitive to changes in earthquake scenario and do not rely on extrapolation for rarely observed events. Because predictions of these proxies are reliable under a variety of earthquake events, we can confidently compare them with simulations. The proposed proxies include correlation of epsilon across periods, ratio of maximum to median response across horizontal orientations, and ratio of inelastic to elastic displacement. The validation framework is applied to example simulations and successfully exposes some parameters that need work, such as variability and correlation of spectral acceleration. Finally, this dissertation investigates the application of simulations to response history analysis and fling-step characterization. A 3D nonlinear structural model is analyzed using recordings and simulations with similar elastic response spectra. The structural performance and resulting design decisions are similar, indicating that simulations are effective for response history analysis subject to certain conditions. To investigate fling-step, we extract fling pulses from a large set of simulations. Extracted fling properties such as amplitude and period are then compared to specially-processed recordings and relevant empirical models for surface displacement and pulse period. Reasonably good agreement is found between simulations, recordings, and empirical models. In general, ground motion simulations are found to be an effective alternative or supplement to recordings in several engineering applications. Because simulation methods are still developing, this work is not intended as an evaluation of existing methods, but rather as a development of procedures that can be used in ongoing work.

Download or read book Seismic Hazard and Risk Analysis written by Jack Baker and published by Cambridge University Press. This book was released on 2021-10-21 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic hazard and risk analyses underpin the loadings prescribed by engineering design codes, the decisions by asset owners to retrofit structures, the pricing of insurance policies, and many other activities. This is a comprehensive overview of the principles and procedures behind seismic hazard and risk analysis. It enables readers to understand best practises and future research directions. Early chapters cover the essential elements and concepts of seismic hazard and risk analysis, while later chapters shift focus to more advanced topics. Each chapter includes worked examples and problem sets for which full solutions are provided online. Appendices provide relevant background in probability and statistics. Computer codes are also available online to help replicate specific calculations and demonstrate the implementation of various methods. This is a valuable reference for upper level students and practitioners in civil engineering, and earth scientists interested in engineering seismology.

Download or read book Measuring Modeling and Predicting the Seismic Site Effect written by Yefei Ren and published by Frontiers Media SA. This book was released on 2024-01-25 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: As recognized universally by both seismology and earthquake engineering communities, the amplitude and frequency content of ground motions are influenced by local site effects, including the effects of near-surface geologic materials, surface topographic and basin effects, and so on. Strong linkage between seismic site effect and earthquake damage has been commonly demonstrated from many past earthquakes. Therefore, quantitative and reliable evaluation of the seismic site effect is one of the crucial aspects in seismic hazard assessment and risk mitigation. With the significant advancement of modern seismic monitoring networks and arrays, huge amounts of high-quality seismic records are now being accumulated. This encourages us to measure the site responses and its associated uncertainty for selected seismic stations by some record-dependent approaches, such as horizontal-to-vertical spectral ratio (HVSR) measurements, generalized spectral inversion (GIT) methods, etc. Machine learning techniques also show significant promise in characterization of the near-surface geologic properties and prediction of site response. These data-driven approaches help us to better understand the physics of spatial and temporal variabilities of ground motions. Due to more and more site-specific data being captured, invoking non-ergodic assumptions in seismic response analysis has recently been a topic of great interest in the community. For specific site response analysis, numerical simulations are carried out to model the dynamic process of seismic waves propagating and scattering in the subsurface strata. With development of modeling capacity, great efforts have been taken to evaluate quantitatively the complex 2D and 3D effects on seismic site response.

Download or read book Tehachapi Renewable Transmission Project TRTP written by and published by . This book was released on 2010 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Methods for Interpreting Geological and Geophysical Data written by Ahmed M. Eldosouky and published by Frontiers Media SA. This book was released on 2024-07-08 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: The introduction and application of advanced geological and geophysical methods can solve many problems related to geoscience. This Research Topic gives a thorough treatment of the interpretation of geological and geophysical data through advanced techniques and integrated approaches. It aims to create a more reliable integration of various geological and geophysical data in an exploration and new findings context weighing the strengths and limitations of the various methods in order to develop geophysical and geological models. It will also focus on the interpretation techniques for evaluating structural and sedimentological (stratigraphical) processes with applications within resource exploration, geohazards, seismology, seabed ecology and global climate.

Download or read book Semi empirical Characterization of Ground Motions Including Source Path and Nonlinear Site Effects written by Emel Seyhan and published by . This book was released on 2013 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to improve the physical understanding of earthquake ground motion characteristics related to source, path and nonlinear site effects and our ability to model those effects with engineering models. This was achieved through four research studies consisting of: (1) calibrating broadband simulation procedures to remove previously recognized sources of bias in distance attenuation and standard deviation; (2) enhancing a site database used for assigning site parameters to ground motion recordings, particularly with regard to the level of rigor and transparency with which the database is populated; (3) leveraging a state-of-the-art ground motion database and recent simulation-based studies to develop a nonlinear site amplification model suitable for use in g̲round m̲otion p̲redictions e̲quations (GMPEs) and relatively simplified building code applications; and (4) developing GMPEs that provides mean and standard deviation of ground motion intensity measures in active crustal regions. The high-frequency component of the simulation procedure considered in this study combines deterministic Fourier amplitude spectra (dependent on source, path, and site models) with random phase. Significantly too-fast distance attenuation bias identified in prior work has been removed by increasing the quality factor (Q). We introduced random site-to-site variations to Fourier amplitudes using a log-normal standard deviation ranging from 0.45 for M 7 to zero for M8 to achieve dispersion terms that are more compatible with those from empirical models but remain lower at large distances (e.g., 100 km). Site database work was performed within the context of the NGA-West 2 project. Starting with the site database from original (2008) NGA project (last edited in 2006), we provided site classifications for 2538 new sites and re-classifications of previous sites. The principal site parameter is the time-averaged shear wave velocity in the upper 30 m Vs30, which is characterized using measurements where available, and proxy-based relationships otherwise. We improved the documentation and consistency of site descriptors used as proxies for the estimation of Vs30, developed evidence-based protocols for Vs30 estimation from available proxies, and augmented estimates of various basin depth parameters. Site factors typically have a small-strain site amplification that captures impedance and resonance effects coupled with nonlinear components. Site factors in current NEHRP Provisions are empirically-derived at relatively small ground motion levels and feature simulation-based nonlinearity. We show that current NEHRP site factors have discrepancies with respect to the site terms in the original NGA GMPEs both in the linear site amplification (especially for Classes B, C, D, and E) and the degree of nonlinearity (Classes C and D). We analyzed the NGA-West 2 dataset and simulation-based models for site amplification to develop a new model. The model has linear and nonlinear additive components. The linear component is fully empirical, being derived from worldwide ground motion data (regional effects were examined but found to not be sufficiently important to be included in the model). The model features linear Vs30-scaling in a log-log sense below a corner velocity (Vc), and no Vs30-scaling for velocities faster than Vc. The nonlinear component is developed from consideration of empirical data analysis and simulation results within a consistent context. The resulting nonlinearity operates principally at short periods and soft soils. This model is suitable for use as a site term in GMPEs and was applied to develop a proposal for updating the NEHRP site factors. The recommended factors remove a discrepancy between the reference condition used in the site factors and the national seismic hazard maps published by USGS. We have developed empirical equations for predicting the average horizontal component of earthquake ground motions from active crustal region earthquakes worldwide. The equations build upon a previous ground-motion model by Boore and Atkinson in 2008. Significant new features of the proposed GMPEs include: modified site terms; a modified magnitude scaling function that produces a higher degree of saturation at large magnitude for high-frequency ground motions; region-specific apparent anelastic attenuation term; basin depth correction factors that are centered on the average level of basin amplification conditional on Vs30; standard deviation terms that depend on M for between-event standard deviations and M-1, Rjb and Vs30-dependent within-event standard deviations. The resulting equations are applicable for events over a magnitude range of 3 to 8.5 for strike-slip or reverse-slip events (M3 to 8 for normal slip events), distance range up to 400 km, and site conditions ranging from Vs30 = 150 to 1500 m/s. The equations are useful for prediction of the ground motion i̲ntensity m̲easures (IMs) PGA, PGV, and PSA at periods T = 0 to 10 sec.

Download or read book Seismic Wave Propagation and Scattering in the Heterogenous Earth written by Haruo Sato and published by Springer Science & Business Media. This book was released on 2008-12-17 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves – generated both by natural earthquakes and by man-made sources – have produced an enormous amount of information about the Earth's interior. In classical seismology, the Earth is modeled as a sequence of uniform horizontal layers (or sperical shells) having different elastic properties and one determines these properties from travel times and dispersion of seismic waves. The Earth, however, is not made of horizontally uniform layers, and classic seismic methods can take large-scale inhomogeneities into account. Smaller-scale irregularities, on the other hand, require other methods. Observations of continuous wave trains that follow classic direct S waves, known as coda waves, have shown that there are heterogeneities of random size scattered randomly throughout the layers of the classic seismic model. This book focuses on recent developments in the area of seismic wave propagation and scattering through the randomly heterogeneous structure of the Earth, with emphasis on the lithosphere. The presentation combines information from many sources to present a coherent introduction to the theory of scattering in acoustic and elastic materials and includes analyses of observations using the theoretical methods developed.

Download or read book New Challenges for Seismic Risk Mitigation in Urban Areas written by Simone Barani and published by Frontiers Media SA. This book was released on 2022-11-30 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Extreme Environmental Events written by and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in the Protection of Museum Collections from Earthquake Damage written by Jerry Podany and published by Getty Publications. This book was released on 2008 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: For nearly three decades, the J. Paul Getty Museum has played a leading role in the development of seismic mitigation for museum collections. Contributors to this volume--ranging from museum conservators, mount makers, and historical archaeologists to seismologists and structural engineers--discuss and illustrate a wide variety of earthquake-mitigation efforts for collections, from the simple and inexpensive to the complex and costly. The book's essays examine the techniques applied to large collections and to small house museums, to exhibition cases containing objects as well as to monumental works of art and historical structures. Approaches range from securing and restraining objects to decoupling them from the ground through a variety of base-isolation mechanisms. These pioneering efforts have been developed in the face of significant challenges since, as any engineer, conservator, or mount maker who has undertaken this work can attest, a small sculpture can often be a far greater challenge to protect than a multistory building.

Download or read book Seismological Research Letters written by and published by . This book was released on 1999 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Earthquake Engineering written by Alberto Bernal and published by CRC Press. This book was released on 1992-01-01 with total page 938 pages. Available in PDF, EPUB and Kindle. Book excerpt: The official proceedings of the 10th world conference on earthquake engineering in Madrid. Coverage includes damage in recent earthquakes, seismic risk and hazard, site effects, structural analysis and design, seismic codes and standards, urban planning, and expert system application.