At the heart of this book is the generalized theoretical approach that is applied to investigate the geoelectrical structure of the Earth’s mantle. It also analyzes the results of regional and global induction sounding of the Earth’s mantle and compares them with the results obtained by other geophysical methods. The generalized theoretical approach employs the Induction Law as a basis for identifying extended relations between magnetic field components, including their plane divergence, impedances and spatial derivatives. The estimations of impedance values and spatial derivatives are performed using the theory of stochastic processes. The book also considers the external sources of magnetic fields used for sounding the Earths mantle from the modern theory perspective, as well as the problem of coincidence of magneto-variation and magnetotelluric methods. Further, it discusses secular variations in the Earth’s resistance caused by non-induction sources, factors that are correlated with the number of earthquakes in the region and shifted in time with global indexes. It is a valuable resource for scientists applying deep induction soundings or interested in the structures of and processes in the Earth’s interior.

Electromagnetic Sounding of the Earth's Interior 2nd edition provides a comprehensive up-to-date collection of contributions, covering methodological, computational and practical aspects of Electromagnetic sounding of the Earth by different techniques at global, regional and local scales. Moreover, it contains new developments such as the concept of self-consistent tasks of geophysics and , 3-D interpretation of the TEM sounding which, so far, have not all been covered by one book. Electromagnetic Sounding of the Earth's Interior 2nd edition consists of three parts: I- EM sounding methods, II- Forward modelling and inversion techniques, and III - Data processing, analysis, modelling and interpretation. The new edition includes brand new chapters on Pulse and frequency electromagnetic sounding for hydrocarbon offshore exploration. Additionally all other chapters have been extensively updated to include new developments. - Presents recently developed methodological findings of the earth's study, including seismoelectrical and renewed magnetovariational approaches - Provides methodological guidelines for Electromagnetic data interpretation in various geological environments - Contains a balanced set of lectures covering all aspects of Electromagnetic sounding at global, regional and local levels along with case studies, highlighting the practical importance of electromagnetic data - Updates current findings in the field, in particular MT, magnetovariational and seismo-electrical methods and the practice of 3D interpretations

Table 1 Earth conductivity profiles Figure File Name Apx. Depth Remarks References 1. Global Models 1939-69 LAPR39 0--1250 global Sq, Dst LAHIRI and PRICE, 1939; PRICE, 1973 RIKI50 0--1400 misc. data sources RIKITAKE. 1950; 1966 MCD057 0--2900 LAPR39 + secular change McDoNALD, 1957 CANT60 100--600 see ECKHARDT et a!. , 1963 CANTWELL, 1960 YUKU65 380--1900 ring current YUKUTAKE, 1965 BANK69 0--1700 ring current BANKS, 1969; 1972 2. Global Models 1970--74 BFRS70 100--700 Sq, Dst 27-d variations BERDICHEVSKY et a!. , 1970; 1973 PRKR70 0--3200 rework BANKS, 1969, data PARKER, 1970 SCJA72 0--1000 pulsations, bays, Sq, Dst SCHMUCKER and JANKOWSKI, 1972 BANK72 230--1250 model summary BANKS, 1972 JADY74 0--2951 Sq, 27-d, annual variations JADY, 1974 FAR074 300--1500 with BFRS70 FAINBERG and ROTANOVA, 1974 SCHM74 0--1000 see HAAK, 1980 SCHMUCKER, 1974 DMRB77 0--1450 all available data DMITRIEV et al. , 1977 Global Models 1974-1983 3. PRKN74 60-430 Sq PARKINSON, 1974 DUCM80 0--2900 annual means DUCRUIX et a!. , 1980 ISIK80 320--2020 Sq, Dst, annual, solar cycle ISIKARA, 1980 ACMC81 0--2875 secular impulse ACACHE et a!. , 1980 ROKI82 350--1200 various methods ROKITYANSKY. 1982 JAPA83 0--1200 Dst JADY and PATERSON, 1983 4. Pacific Models LAUN74 0--500 near Calif. ; see DRURY, 1978 LAUNAY, 1975 LARSEN, 1975 LAHA75 0--800 Hawaii 7-1350 FILL80 NE Pacific FILLOUX, 1980 LAW and GREENHOUSE, LWGR81 0--200 Juan de Fuca 1981 0--250 Juan de Fuca OLDENBURG et a!. , 1984 OLJA84 OLCA84 0-250 near Calif. OLDENBURG et al. , 1984 OLNC84 0--250 N. cent. Pacific OLDENBURG et ai.

Electrical conductivity is a parameter which characterizes composition and physical state of the Earth's interior. Studies of the state equations of solids at high temperature and pressure indicate that there is a close relation be tween the electrical conductivity of rocks and temperature. Therefore, measurements of deep conductivity can provide knowledge of the present state and temperature of the Earth's crust and upper mantle matter. Infor mation about the temperature of the Earth's interior in the remote past is derived from heat flow data. Experimental investigation of water-containing rocks has revealed a pronounced increase of electrical conductivity in the temperature range D from 500 to 700 DC which may be attributed to the beginning of fractional melting. Hence, anomalies of electrical conductivity may be helpful in identitying zones of melting and dehydration. The studies of these zones are perspective in the scientific research of the mobile areas of the Earth's crust and upper mantle where tectonic movements, processes ofthe region al metamorphism and of forming mineral deposits are most intensive. Thus, in the whole set of research on physics of the Earth the studies of electrical conductivity of deep-seated rocks appear, beyond doubt, very important.

This volume serves as an introduction to modern magnetotellurics originating with the pioneering work of Tikhonov and Cagniard. It presents a comprehensive summary of theoretical and methodological aspects of magnetotellurics. It provides a bridge between textbooks on electrical prospecting and numerous papers on magnetotelluric methods scattered among various geophysical journals and collections. The book has been written in the terms of the theory of ill-posed problems and contains a special chapter encouraging readers to master the elements of this theory that defines the philosophy of the physical experiment. The book thus offers the connected and consistent account of the principles of magnetotellurics from that single viewpoint. The book also brings together developments from many sources and involves some little-known results developed in Russia in Tikhonov's magnetotellurics school. Of particular interest are concluding chapters of the book that demonstrate the potential of magnetotellurics in oil and gas surveys, including discovery of the Urengoy gas field in Western Siberia, one of the largest gas fields in the world. This potential also is revealed in studies of the earth's crust and upper mantle.

Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 125 (1987), No. 2/3

This reference encompasses the fields of Geomagnetism and Paleomagnetism in a single volume. Both sciences have applications in navigation, in the search for minerals and hydrocarbons, in dating rock sequences, and in unraveling past geologic movements such as plate motions they have contributed to a better understanding of the Earth. The book describes in fine detail the current state of knowledge and provides an up-to-date synthesis of the most basic concepts. It is an indispensable working tool not only for geophysicists and geophysics students but also for geologists, physicists, atmospheric and environmental scientists, and engineers.