Download or read book Full 3d Waveform Inversions and Their Applications in Southern California written by En-Jui Lee and published by . This book was released on 2013 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ground motion recordings have been used widely in analyzing physical properties of the Earth materials and mechanism of earthquakes. The recent advances in computational technology and numerical methods allow seismologists to accurately simulate wave propagation in 3D strongly heterogeneous media and opened up the possibility of extracting more information from waveform recordings for seismic tomography and earthquake source inversion. Furthermore, body wave and surface wave phases can be all used to benefit seismic imaging and source inversion without additional assumptions in the full-wave method. To examine the advantages of full-wave method, we have implemented our tomogaphic and earthquake source inversion algorithms in Southern California where has complex geological structures and has well distributed seismic broadband arrays. We have developed a semi-automated waveform segmentation and selection algorithm and the tool has been applied to large amounts of waveforms for our full-wave earthquake source and tomographic inversions. In our earthquake source inversion algorithm, the receiver Green's tensors, which comprise the spatial-temporal displacements produced by the three orthogonal unit impulsive point forces acting at the receiver, are computed in our updated 3D velocity model. The receiver Green's tensors are stored in disk for efficiently generating synthetic seismograms by using reciprocity between stations and any spatial grid point in our model, and therefore our source inversion algorithm could rapidly invert earthquake source parameters and could provide physics-based ground motion predictions. In our tomographic inversion, the velocity model has been iteratively improved by using the scattering-integral and adjoin-wavefield methods. To accelerate iterations, the LSQR algorithm has been paralleled and optimized for solving our large tomographic inversion systems. The optimized LSQR algorithm reduces both communication cost and memory usage during inversions, so the calculation time and required computational resources are significantly reduced. After 26 iterations, the new crustal velocity model reveals a strongly heterogeneous crustal structure in Southern California. In addition, our tomography also reveals many features that are not shown in the initial model, but have been found in other independent studies. The new tomography enables more accurate physics-based seismic hazard applications and the tectonic reconstruction of Southern California.

Download or read book Full 3D Seismic Waveform Inversion written by Po Chen and published by Springer. This book was released on 2015-09-10 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces a methodology for solving the seismic inverse problem using purely numerical solutions built on 3D wave equations and which is free of the approximations or simplifications that are common in classical seismic inversion methodologies and therefore applicable to arbitrary 3D geological media and seismic source models. Source codes provided allow readers to experiment with the calculations demonstrated and also explore their own applications.

Download or read book Full Seismic Waveform Modelling and Inversion written by Andreas Fichtner and published by Springer Science & Business Media. This book was released on 2010-11-16 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent progress in numerical methods and computer science allows us today to simulate the propagation of seismic waves through realistically heterogeneous Earth models with unprecedented accuracy. Full waveform tomography is a tomographic technique that takes advantage of numerical solutions of the elastic wave equation. The accuracy of the numerical solutions and the exploitation of complete waveform information result in tomographic images that are both more realistic and better resolved. This book develops and describes state of the art methodologies covering all aspects of full waveform tomography including methods for the numerical solution of the elastic wave equation, the adjoint method, the design of objective functionals and optimisation schemes. It provides a variety of case studies on all scales from local to global based on a large number of examples involving real data. It is a comprehensive reference on full waveform tomography for advanced students, researchers and professionals.

Download or read book Monitoring the Comprehensive Nuclear Test Ban Treaty Surface Waves written by Anatoli L. Levshin and published by Springer Science & Business Media. This book was released on 2001-09-01 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: On September 1996, the United Nations General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), prohibiting nuclear explosions worldwide, in all environments. The treaty calls for a global verification system, including a network of 321 monitoring stations distributed around the globe, a data communications network, an international data center (IDC), and on-site inspections to verify compliance. Seismic methods play the lead role in monitoring the CTBT. This volume concentrates on the measurement and use of surface waves in monitoring the CTBT. Surface waves have three principal applications in CTBT monitoring: to help discriminate nuclear explosions from other sources of seismic energy, to provide mathematical characterizations of the seismic energy that emanates from seismic sources, and to be used as data in inversion for the seismic velocity structure of the crust and uppermost mantle for locating small seismic events regionally. The papers in this volume fall into two general categories: the development and/or application of methods to summarize information in surface waves, and the use of these summaries to advance the art of surface-wave identification, measurement, and source characterization. These papers cut across essentially all of the major applications of surface waves to monitoring the CTBT. This volume therefore provides a general introduction to the state of research in this area and should be useful as a guide for further exploration.

Download or read book Advances and Applications of Passive Seismic Source Characterization written by Lei Li and published by Frontiers Media SA. This book was released on 2023-10-09 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Source characterization is a fundamental task of passive seismic monitoring. Spatial-temporal evolution of both, point sources and finite-fault source, provides essential information for timely seismic hazard management and advanced analysis of the seismicity in the monitored areas. In the last few decades, the rise of dense seismic arrays, increase of high-performance computing resources, and development of advanced array-based techniques lead to studies using recorded wavefields in great detail. Full waveform inversion can invert passive seismic source parameters with an iterative framework, which connects the delay-and-sum imaging technique and kernel-based inversion strategy. Moreover, emerging technologies like distributed acoustic sensing and machine learning also have great potential in advancing passive seismic imaging and source characterization. Besides, non-earthquake sources and ambient noise, as unconventional and passive sources, are also undergoing rapid development in infrastructure monitoring and subsurface imaging, due to the emergence of sensitive sensors and modern techniques like seismic interferometry.

Download or read book Applications of Data Assimilation and Inverse Problems in the Earth Sciences written by Alik Ismail-Zadeh and published by Cambridge University Press. This book was released on 2023-06-30 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many contemporary problems within the Earth sciences are complex, and require an interdisciplinary approach. This book provides a comprehensive reference on data assimilation and inverse problems, as well as their applications across a broad range of geophysical disciplines. With contributions from world leading researchers, it covers basic knowledge about geophysical inversions and data assimilation and discusses a range of important research issues and applications in atmospheric and cryospheric sciences, hydrology, geochronology, geodesy, geodynamics, geomagnetism, gravity, near-Earth electron radiation, seismology, and volcanology. Highlighting the importance of research in data assimilation for understanding dynamical processes of the Earth and its space environment and for predictability, it summarizes relevant new advances in data assimilation and inverse problems related to different geophysical fields. Covering both theory and practical applications, it is an ideal reference for researchers and graduate students within the geosciences who are interested in inverse problems, data assimilation, predictability, and numerical methods.

Download or read book Theoretical Global Seismology written by F. A. Dahlen and published by Princeton University Press. This book was released on 2020-08-04 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt: After every major earthquake, the Earth rings like a bell for several days. These free oscillations of the Earth and the related propagating body and surface waves are routinely detected at broad-band seismographic stations around the world. In this book, F. A. Dahlen and Jeroen Tromp present an advanced theoretical treatment of global seismology, describing the normal-mode, body-wave, and surface-wave methods employed in the determination of the Earth's three-dimensional internal structure and the source mechanisms of earthquakes. The authors provide a survey of both the history of global seismological research and the major theoretical and observational advances made in the past decade. The book is divided into three parts. In the first, "Foundations," Dahlen and Tromp give an extensive introduction to continuum mechanics and discuss the representation of seismic sources and the free oscillations of a completely general Earth model. The resulting theory should provide the basis for future scientific discussions of the elastic-gravitational deformation of the Earth. The second part, "The Spherical Earth," is devoted to the free oscillations of a spherically symmetric Earth. In the third part, "The Aspherical Earth," the authors discuss methods of dealing with the Earth's three-dimensional heterogeneity. The book is concerned primarily with the forward problem of global seismology--detailing how synthetic seismograms and spectra may be calculated and interpreted. As a long-needed unification of theories in global seismology, the book will be important to graduate students and to professional seismologists, geodynamicists, and geomagnetists, as well as to astronomers who study the free oscillations of the Sun and other stars.

Download or read book 3D Multi parameters Full Waveform Inversion for Challenging 3D Elastic Land Targets written by Phuong-Thu Trinh and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic imaging of onshore targets is very challenging due to the 3D complex near-surface-related effects. In such areas, the seismic wavefield is dominated by elastic and visco-elastic effects such as highly energetic and dispersive surface waves. The interaction of elastic waves with the rough topography and shallow heterogeneities leads to significant converted and scattering energies, implying that both accurate 3D geometry representation and correct physics of the wave propagation are required for a reliable structured imaging. In this manuscript, we present an efficient and flexible full waveform inversion (FWI) strategy for velocity model building in land, specifically in foothill areas.Viscoelastic FWI is a challenging task for current acquisition deployment at the crustal scale. We propose an efficient formulation based on a time-domain spectral element method (SEM) on a flexible Cartesian-based mesh, in which the topography variation is represented by an accurate high-order geometry interpolation. The wave propagation is described by the anisotropic elasticity and isotropic attenuation physics. The numerical implementation of the forward problem includes efficient matrix-vector products for solving second-order elastodynamic equations, even for completely deformed 3D geometries. Complete misfit gradient expressions including attenuation contribution spread into density, elastic parameters and attenuation factors are given in a consistent way. Combined adjoint and forward fields recomputation from final state and previously saved boundary values allows the estimation of gradients with no I/O efforts. Two-levels parallelism is implemented over sources and domain decomposition, which is necessary for 3D realistic configuration. The gradient preconditioning is performed by a so-called Bessel filter using an efficient differential implementation based on the SEM discretization on the forward mesh instead of the costly convolution often-used approach. A non-linear model constraint on the ratio of compressional and shear velocities is introduced into the optimization process at no extra cost.The challenges of the elastic multi-parameter FWI in complex land areas are highlighted through synthetic and real data applications. A 3D synthetic inverse-crime illustration is considered on a subset of the SEAM phase II Foothills model with 4 lines of 20 sources, providing a complete 3D illumination. As the data is dominated by surface waves, it is mainly sensitive to the S-wave velocity. We propose a two-steps data-windowing strategy, focusing on early body waves before considering the entire wavefield, including surface waves. The use of this data hierarchy together with the structurally-based Bessel preconditioning make possible to reconstruct accurately both P- and S-wavespeeds. The designed inversion strategy is combined with a low-to-high frequency hierarchy, successfully applied to the pseudo-2D dip-line survey of the SEAM II Foothill dataset. Under the limited illumination of a 2D acquisition, the model constraint on the ratio of P- and S-wavespeeds plays an important role to mitigate the ill-posedness of the multi-parameter inversion process. By also considering surface waves, we manage to exploit the maximum amount of information in the observed data to get a reliable model parameters estimation, both in the near-surface and in deeper part.The developed FWI frame and workflow are finally applied on a real foothill dataset. The application is challenging due to sparse acquisition design, especially noisy recording and complex underneath structures. Additional prior information such as the logs data is considered to assist the FWI design. The preliminary results, only relying on body waves, are shown to improve the kinematic fit and follow the expected geological interpretation. Model quality control through data-fit analysis and uncertainty studies help to identify artifacts in the inverted models.

Download or read book Seismic Imaging Fault Damage and Heal written by Yong-Gang Li and published by Walter de Gruyter GmbH & Co KG. This book was released on 2014-05-21 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting current approaches in observational and computational seismology, this book introduces advanced methods and techniques by means of case studies in earthquake research. Among others these include solving inverse seismologic problems, tomography for structure imaging, characterizing fault damage and healing, seismicity analysis for determining pre-shock moment release, and coupled solid-fluid models.

Download or read book Earthquake Engineering written by Halil Sezen and published by BoD – Books on Demand. This book was released on 2012-08-08 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent major earthquakes around the world have shown the vulnerability of infrastructure and the need for research to better understand the nature of seismic events and their effects on structures. As a result, earthquake engineering research has been expanding as more and more data become available from a large array of seismic instruments, large scale experiments and numerical simulations. The first part of this book presents results from some of the current seismic research work including three-dimensional wave propagation in different soil media, seismic loss assessment, probabilistic hazard analysis, geotechnical problems including soil-structure interaction. The second part of the book focuses on the seismic behavior of structures including historical and monumental structures, bridge embankments, and different types of bridges and bearings.

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 The Seismic Wavefield Volume 1 Introduction and Theoretical Development written by B. L. N. Kennett and published by Cambridge University Press. This book was released on 2001-11-12 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a guide to understanding of seismograms for graduate students, researchers, professionals in academia and the petroleum industry.

Download or read book Seismological Research Letters written by and published by . This book was released on 2006 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Inversion written by Yanghua Wang and published by John Wiley & Sons. This book was released on 2016-09-15 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic inversion aims to reconstruct a quantitative model of the Earth subsurface, by solving an inverse problem based on seismic measurements. There are at least three fundamental issues to be solved simultaneously: non-linearity, non-uniqueness, and instability. This book covers the basic theory and techniques used in seismic inversion, corresponding to these three issues, emphasising the physical interpretation of theoretical concepts and practical solutions. This book is written for master and doctoral students who need to understand the mathematical tools and the engineering aspects of the inverse problem needed to obtain geophysically meaningful solutions. Building on the basic theory of linear inverse problems, the methodologies of seismic inversion are explained in detail, including ray-impedance inversion and waveform tomography etc. The application methodologies are categorised into convolutional and wave-equation based groups. This systematic presentation simplifies the subject and enables an in-depth understanding of seismic inversion. This book also provides a practical guide to reservoir geophysicists who are attempting quantitative reservoir characterisation based on seismic data. Philosophically, the seismic inverse problem allows for a range of possible solutions, but the techniques described herein enable geophysicists to exclude models that cannot satisfy the available data. This book summarises the author’s extensive experience in both industry and academia and includes innovative techniques not previously published.

Download or read book Treatise on Geophysics written by and published by Elsevier. This book was released on 2015-04-17 with total page 5604 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treatise on Geophysics, Second Edition, is a comprehensive and in-depth study of the physics of the Earth beyond what any geophysics text has provided previously. Thoroughly revised and updated, it provides fundamental and state-of-the-art discussion of all aspects of geophysics. A highlight of the second edition is a new volume on Near Surface Geophysics that discusses the role of geophysics in the exploitation and conservation of natural resources and the assessment of degradation of natural systems by pollution. Additional features include new material in the Planets and Moon, Mantle Dynamics, Core Dynamics, Crustal and Lithosphere Dynamics, Evolution of the Earth, and Geodesy volumes. New material is also presented on the uses of Earth gravity measurements. This title is essential for professionals, researchers, professors, and advanced undergraduate and graduate students in the fields of Geophysics and Earth system science. Comprehensive and detailed coverage of all aspects of geophysics Fundamental and state-of-the-art discussions of all research topics Integration of topics into a coherent whole

Download or read book Geophysical exploration of the solar system written by Cedric Schmelzbach and published by Academic Press. This book was released on 2021-08-31 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Formation and Structure of Planets, Volume 62 in the Advances in Geophysics series, highlights new chapters on a variety of topics in the field, including The evolution of multi-method imaging of structures and processes in environmental geophysics, An introduction to variational inference in Geophysical inverse problems, Moment tensor inversion, and more. Provides high-level reviews of the latest innovations in geophysics Written by recognized experts in the field Presents an essential publication for researchers in all fields of geophysics

Download or read book Seismology and Structure of the Earth written by Barbara Romanowicz and published by Elsevier. This book was released on 2010-04-20 with total page 873 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treatise on Geophysics: Seismology and Structure of the Earth, Volume 1, provides a comprehensive review of the state of knowledge on the Earths structure and earthquakes. It addresses various aspects of structural seismology and its applications to other fields of Earth sciences. The book is organized into four parts. The first part principally covers theoretical developments and seismic data analysis techniques from the end of the nineteenth century until the present, with the main emphasis on the development of instrumentation and its deployment. The second part reviews the status of knowledge on the structure of the Earths shallow layers, starting with a global review of the Earth's crustal structure. The third part focuses on the Earth's deep structure, divided into its main units: the upper mantle, the transition zone and upper-mantle discontinuities, the D region at the base of the mantle, and the Earth's core. The fourth part comprises two chapters which discuss constraints on Earth structure from fields other than seismology: mineral physics and geodynamics. Self-contained volume starts with an overview of the subject then explores each topic with in depth detail Extensive reference lists and cross references with other volumes to facilitate further research Full-color figures and tables support the text and aid in understanding Content suited for both the expert and non-expert