Download or read book Global Full Waveform Tomography Using the Spectral Element Method written by Scott Winfield French and published by . This book was released on 2014 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: The radially anisotropic shear-velocity structure of the earth's mantle provides a critical window on the interior dynamics of the planet, with isotropic variations interpretable in terms of thermal and compositional heterogeneity and anisotropy in terms of flow. Indeed, more than 30 years after the advent of global seismic tomography, many open questions remain regarding the dual roles of temperature and composition in shaping mantle convection, as well as interactions between different dominant scales of convective phenomena. To this end, we use full-waveform inversion of the long-period teleseismic wavefield to image radially anisotropic shear-wave velocity at the scale of the entire globe. In particular, we use a technique which we have termed the "hybrid" waveform-inversion approach, which combines the accuracy and generality of the spectral finite element method (SEM) for forward modeling of the global wavefield, with non-linear asymptotic coupling theory for efficient inverse modeling. This hybrid technique helps considerably in making SEM-based global waveform inversion tractable, as it allows for the use of a rapidly converging Gauss-Newton scheme for optimization of the underlying seismic model. We take additional steps to reduce the cost of these inversions using novel techniques for treatment of the earth's crust. Namely, naive modeling of thinly layered crustal structure can lead to an overly restrictive time-stability condition in the SEM, which in turn drives up the cost these simulations. Instead, taking advantage of the physics of long-period wave propagation, we introduce alternative parameterizations of crustal structure which appear identical to the wavefield, but relax these constraints on stability. We approach this imaging problem in an iterative fashion, hoping to learn something about the earth's interior at each step. First, we present our work focused on the upper mantle and transition zone (≤ 800km depth) in the form of the global model SEMum2, discussing both its development and general properties. Second, we take a detailed look at novel structures in SEMum2 - namely, never-before-seen low-velocity structures in the upper mantle beneath the ocean basins, showing intriguing correlations with other geophysical observables (e.g. absolute plate motions and the geoid). Third, we move on to imaging of the whole mantle, examining the relationships between different scales of convective phenomena in the upper and lower mantle, and particularly those previously seen in SEMum2. Finally, we discuss novel computational aspects of our work, focusing specifically on applications of the partitioned global address-space model of parallel computation to the large-scale data-driven calculations underlying our hybrid inversion approach.
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 The Finite Difference Modelling of Earthquake Motions written by Peter Moczo and published by Cambridge University Press. This book was released on 2014-04-24 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among all the numerical methods in seismology, the finite-difference (FD) technique provides the best balance of accuracy and computational efficiency. This book offers a comprehensive introduction to FD and its applications to earthquake motion. Using a systematic tutorial approach, the book requires only undergraduate degree-level mathematics and provides a user-friendly explanation of the relevant theory. It explains FD schemes for solving wave equations and elastodynamic equations of motion in heterogeneous media, and provides an introduction to the rheology of viscoelastic and elastoplastic media. It also presents an advanced FD time-domain method for efficient numerical simulations of earthquake ground motion in realistic complex models of local surface sedimentary structures. Accompanied by a suite of online resources to help put the theory into practice, this is a vital resource for professionals and academic researchers using numerical seismological techniques, and graduate students in earthquake seismology, computational and numerical modelling, and applied mathematics.
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 Computational Seismology written by Heiner Igel and published by Oxford University Press. This book was released on 2017 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introductory text to a range of numerical methods used today to simulate time-dependent processes in Earth science, physics, engineering and many other fields. It looks under the hood of current simulation technology and provides guidelines on what to look out for when carrying out sophisticated simulation tasks.
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 Seismic Ambient Noise written by Nori Nakata and published by Cambridge University Press. This book was released on 2019-03-21 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of seismic ambient noise, covering observations, physical origins, modelling, processing methods and applications in imaging and monitoring.
Download or read book Wavefield Inversion written by Armand Wirgin and published by Springer Science & Business Media. This book was released on 2000-04-19 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an up-to-date presentation of a broad range of contemporary problems in inverse scattering involving acoustic, elastic and electromagnetic waves. Descriptions will be given of traditional (but still in use and subject to on-going improvements) and more recent methods for identifying either: a) the homogenized material parameters of (spatially) unbounded or bounded heterogeneous media, or b) the detailed composition (spatial distribution of the material parameters) of unbounded or bounded heterogeneous media, or c) the location, shape, orientation and material characteristics of an object embedded in a wellcharacterized homogeneous, homogenized or heterogeneous unbounded or bounded medium, by inversion of reflected, transmitted or scattered spatiotemporal recorded waveforms resulting from the propagation of probe radiation within the medium.
Download or read book Conference on Inverse Scattering Theory and Application written by J. Bee Bednar and published by SIAM. This book was released on 1983-01-01 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic Tomography written by G. Nolet and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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: A comprehensive reference on data assimilation and inverse problems, and their applications across a broad range of geophysical disciplines, ideal for researchers and graduate students. It highlights the importance of data assimilation for understanding dynamical processes of the Earth and its space environment, and summarises recent advances.
Download or read book Seismic Inversion written by Gerard T. Schuster and published by SEG Books. This book was released on 2017-07-01 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. The primary application is for inverting reflection and/or transmission data from engineering or exploration surveys, but the methods described also can be used for earthquake studies. Seismic Inversion will be of benefit to scientists and advanced students in engineering, earth sciences, and physics. It is desirable that the reader has some familiarity with certain aspects of numerical computation, such as finite-difference solutions to partial differential equations, numerical linear algebra, and the basic physics of wave propagation. For those not familiar with the terminology and methods of seismic exploration, a brief introduction is provided. To truly understand the nuances of seismic inversion, we have to actively practice what we preach (or teach). Therefore, computational labs are provided for most of the chapters, and some field data labs are given as well.
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 Numerical Modeling of Seismic Wave Propagation written by Johan O. A. Robertsson and published by SEG Books. This book was released on 2012 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: The decades following SEG's 1990 volume on numerical modeling showed a step change in the application and use of full wave equation modeling methods enabled by the increase in computational power. Full waveform inversion, reverse time migration, and 3D elastic finite-difference synthetic data generation are examples. A searchable CD is included.
Download or read book Seismic Wave Propagation in Stratified Media written by Brian Kennett and published by ANU E Press. This book was released on 2009-05-01 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic Wave Propagation in Stratified Media presents a systematic treatment of the interaction of seismic waves with Earth structure. The theoretical development is physically based and is closely tied to the nature of the seismograms observed across a wide range of distance scales - from a few kilometres as in shallow reflection work for geophysical prospecting, to many thousands of kilometres for major earthquakes. A unified framework is presented for all classes of seismic phenomena, for both body waves and surface waves. Since its first publication in 1983 this book has been an important resource for understanding the way in which seismic waves can be understood in terms of reflection and transmission properties of Earth models, and how complete theoretical seismograms can be calculated. The methods allow the development of specific approximations that allow concentration on different seismic arrivals and hence provide a direct tie to seismic observations.
Download or read book Numerical Mathematics written by Alfio Quarteroni and published by Springer. This book was released on 2017-01-26 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is to provide the mathematical foundations of numerical methods, to analyze their basic theoretical properties and to demonstrate their performances on examples and counterexamples. Within any specific class of problems, the most appropriate scientific computing algorithms are reviewed, their theoretical analyses are carried out and the expected results are verified using the MATLAB software environment. Each chapter contains examples, exercises and applications of the theory discussed to the solution of real-life problems. While addressed to senior undergraduates and graduates in engineering, mathematics, physics and computer sciences, this text is also valuable for researchers and users of scientific computing in a large variety of professional fields.
Download or read book Encyclopedia of Solid Earth Geophysics written by Harsh Gupta and published by Springer Science & Business Media. This book was released on 2011-06-29 with total page 1579 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past few decades have witnessed the growth of the Earth Sciences in the pursuit of knowledge and understanding of the planet that we live on. This development addresses the challenging endeavor to enrich human lives with the bounties of Nature as well as to preserve the planet for the generations to come. Solid Earth Geophysics aspires to define and quantify the internal structure and processes of the Earth in terms of the principles of physics and forms the intrinsic framework, which other allied disciplines utilize for more specific investigations. The first edition of the Encyclopedia of Solid Earth Geophysics was published in 1989 by Van Nostrand Reinhold publishing company. More than two decades later, this new volume, edited by Prof. Harsh K. Gupta, represents a thoroughly revised and expanded reference work. It brings together more than 200 articles covering established and new concepts of Geophysics across the various sub-disciplines such as Gravity, Geodesy, Geomagnetism, Seismology, Seismics, Deep Earth Processes, Plate Tectonics, Thermal Domains, Computational Methods, etc. in a systematic and consistent format and standard. It is an authoritative and current reference source with extraordinary width of scope. It draws its unique strength from the expert contributions of editors and authors across the globe. It is designed to serve as a valuable and cherished source of information for current and future generations of professionals.
