Download or read book Two dimensional Constrained Anisotropic Inversion of Magnetotelluric Data written by Xiaoming Chen and published by . This book was released on 2012 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two dimensional Modeling and Inversion of the Controlled source Electromagnetic and Magnetotelluric Methods Using Finite Elements and Full space PDE constrained Optimization Strategies written by Savitri Galiana Blanch and published by . This book was released on 2016 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The controlled-source electromagnetics (CSEM) and magnetotellurics (MT) methods arecommon geophysical tools for imaging the electrical properties of the Earth's subsurfaceand are employed independently, jointly, and in combination with other geophysical tech-niques. In order to appreciate measured data, both methods require forward and inversemodeling of the electrically conductive subsurface with the ultimate goal of finding a fea-sible model for which the simulated data reasonably fits the observations. Naturally, thepotential goodness of this fit not only depends on the error in the measured data and on thenumerical error but also on the degree of physical approximation inferred by numericalmodeling. Therefore, active research focuses on new methods for modeling and inversionto obtain accurate and reliable models of the Earth's structure in increasingly complexscenarios. A first step is to enhance modeling approximations by taking into account physical fac-tors such as anisotropy, topography or realistic sources. Second, in order to accommodatethese factors in a modeling and inversion program and to deal with typically large datasets, numerical methods need to be assessed in terms of solution accuracy, time efficiencyand memory demand. The finite elements (FE) modeling methods are known to offer mostflexibility in model geometry and contain quality control mechanisms for the solution, likeshape function order and adaptive mesh refinement. Most emerging modeling programsare based on FE, appreciating significant advantages, but nearly all inverse modeling pro-grams to date are still based on finite differences (FD) or integral equation (IE) methods. Furthermore, inverse modeling developed for electromagnetic (EM) data is generallybased on gradient methods and is formulated in a reduced space, where the only optimiza-tion variables are the model parameters, that is the electric conductivity of the subsurface. Originally, the inverse problem is stated for the EM fields and the conductivity parameter, and constrained by partial differential equations (PDEs) governing the EM field variables. The reduced-space strategy eliminates the field variables by applying equality constraintsand solving then, the unconstrained problem in the reduced-space of model parameters. Acommon drawback of such methods is the repeated costly computation of the solution ofthe forward problem and of the Jacobian matrix of sensitivities (for Newton's based meth-ods). In contrast, it is also possible to solve the inverse problem in the full-space of modelparameters, including both the EM field variables and the electric conductivity parameter. Solving the PDE-constrained optimization problem directly (full-space) has the advantagethat it is only necessary to solve exactly the PDEs at the very end of the optimization provicess but it comes at the cost of many more optimization variables and of the presence ofequality constraints. Also, in particular, within a FE framework, the PDE-constrained op-timization problem provides the additional benefit to include sophisticated FE techniquesin the inversion process, such as adaptive mesh refinement. This thesis develops a robust and versatile adaptive unstructured mesh FE programto numerically model the total field for two-dimensional (2-D) anisotropic CSEM and MTdata, allowing for arbitrarily oriented, three-dimensional (3-D) sources. To represent 3-DCSEM sources for a 2-D physical model, a two-and-a-half-dimensional (2.5-D) approxi-mation is employed. The FE formulations are derived for both methods, for isotropic andanisotropic subsurface conductivity structures. Although the anisotropic case is not general, it includes vertical and dipping anisotropy. The accuracy of the solution is controlledand improved by an adaptive mesh refinement algorithm usinga-posteriorierror estimator methods."--TDX.

Download or read book Occam2 written by Catherine DeGroot-Hedlin and published by . This book was released on 1991 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Magnetotelluric Method written by Alan D. Chave and published by Cambridge University Press. This book was released on 2012-04-26 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: The magnetotelluric method is a technique for imaging the electrical conductivity and structure of the Earth, from the near surface down to the 410 km transition zone and beyond. This book forms the first comprehensive overview of magnetotellurics, from the salient physics and its mathematical representation to practical implementation in the field, data processing, modeling and geological interpretation. Electromagnetic induction in 1-D, 2-D and 3-D media is explored, building from first principles, and with thorough coverage of the practical techniques of time series processing, distortion, numerical modeling and inversion. The fundamental principles are illustrated with a series of case histories describing geological applications. Technical issues, instrumentation and field practices are described for both land and marine surveys. This book provides a rigorous introduction to magnetotellurics for academic researchers and advanced students, and will be of interest to industrial practitioners and geoscientists wanting to incorporate rock conductivity into their interpretations.

Download or read book Fast and Stable Two dimensional Inversion of Magnetotelluric Data written by Patricia Pastana De Lugão and published by . This book was released on 1997 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 The Inversion of Two dimensional Magnetotelluric and Magnetic Variation Data written by Hjálmar Eysteinsson and published by . This book was released on 1988 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Electromagnetic Geophysical Exploration written by Jin Li and published by Frontiers Media SA. This book was released on 2024-01-19 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromagnetic exploration is one of the earliest and most widely used geophysical exploration techniques. Electromagnetic methods, such as magnetotelluric (MT), audio magnetotelluric (AMT), transient electromagnetic method (TEM), and controlled source electromagnetic method (CSEM), have made a great contribution to industrialization and urbanization by discovering underground deposits of various resources. Driven by the latest progress in electronics and intelligent algorithms, electromagnetic exploration is developing at a high speed. Many challenges faced by traditional geophysical methods are now solvable. Emerging sensing technology and signal processing technology greatly improves the accuracy of electromagnetic methods in many applications. At the same time, such technologies promoted the development of new geophysical theories and methods.

Download or read book Inversion of Geophysical Data written by Laurence R. Lines and published by . This book was released on 1988 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal written by Canadian Society of Exploration Geophysicists and published by . This book was released on 1990 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Inverse Theory and Applications in Geophysics written by Michael S. Zhdanov and published by Elsevier. This book was released on 2015-07-15 with total page 731 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geophysical Inverse Theory and Applications, Second Edition, brings together fundamental results developed by the Russian mathematical school in regularization theory and combines them with the related research in geophysical inversion carried out in the West. It presents a detailed exposition of the methods of regularized solution of inverse problems based on the ideas of Tikhonov regularization, and shows the different forms of their applications in both linear and nonlinear methods of geophysical inversion. It's the first book of its kind to treat many kinds of inversion and imaging techniques in a unified mathematical manner.The book is divided in five parts covering the foundations of the inversion theory and its applications to the solution of different geophysical inverse problems, including potential field, electromagnetic, and seismic methods. Unique in its focus on providing a link between the methods used in gravity, electromagnetic, and seismic imaging and inversion, it represents an exhaustive treatise on inversion theory.Written by one of the world's foremost experts, this work is widely recognized as the ultimate researcher's reference on geophysical inverse theory and its practical scientific applications. - Presents state-of-the-art geophysical inverse theory developed in modern mathematical terminology—the first to treat many kinds of inversion and imaging techniques in a unified mathematical way - Provides a critical link between the methods used in gravity, electromagnetic, and seismic imaging and inversion, and represents an exhaustive treatise on geophysical inversion theory - Features more than 300 illustrations, figures, charts and graphs to underscore key concepts - Reflects the latest developments in inversion theory and applications and captures the most significant changes in the field over the past decade

Download or read book Inversion of Magnetotelluric Data for a One dimensional Conductivity written by Kenneth Patrick Whittall and published by . This book was released on 1992 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Inversion of Two dimensional Magnetotelluric Data written by Ai Jun Zhang and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cumulative Index Geophysics Journal of the Society of Exploration Geophysicists 1936 1988 Inclusive Early Geophysical Papers Geophysics the Leading Edge of Exploration selected Papers 1982 88 Inclusive written by William J. Zwart and published by . This book was released on 1990 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Geomagnetism and Geoelectricity written by and published by . This book was released on 1993 with total page 962 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1986 with total page 1066 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Practical Magnetotellurics written by Fiona Simpson and published by Cambridge University Press. This book was released on 2005-02-03 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publisher Description