10.------------------------, 10.------------------------. N ::IE ~ w ~ '" "'0.1 \~ 0 M z SIDE VIEW PLAN VIEW 0.01 LI --'---'---LLL-'---LLLlI ~-L---"---LLL..ll..L.LJ'-':';;' 0.01 1 100 10 100 fr Fig. 1. The behavior of the magnetic and electric fields from a vertical magnetic dipole source at the surface of the earth (after Wait [1951,1955]). earth, the experimental curve so plotted should have the same shape as a portion of the ap propriate theoretical curve, but with the ordinates and abscissas shifted by an amount dependent on the resistivity. The conductivity can be determined from the amount of shift between the field data and the theoretical curve. A detailed description of the curve matching procedure is found in a text by Keller and Frischknecht (1966). The curve matching procedure, though used, has several disadvantages. Measurements must be made over a diagnostic portion of the theoretical curve, one in which there is some curvature, so that the amount of shift required to make a match can be determined uniquely. This means that the approximate conductivity of the earth must be known when measurements are made. Secondly, determination of a single value of conductivity requires measurements made over a wide range of frequencies. This would appear to be wasteful of data, inasmuch as the equations indicate that a single measurement at a single frequency should be enough to de termine conductivity.

As a slag heap, the result of strip mining, creeps closer to his house in the Ohio hills, fifteen-year-old M. C. is torn between trying to get his family away and fighting for the home they love.

This volume describes how controlled-source electromagnetic (CSEM) methods are used to determine the electrical conductivity and hydrocarbon content of the upper few kilometres of the Earth, on land and at sea. The authors show how the signal-to-noise ratio of the measured data may be maximised via suitable choice of acquisition and processing parameters and selection of subsequent data analysis procedures. Complete impulse responses for every electric and magnetic source and receiver configuration are derived, providing a guide to the expected response for real data. 1-D, 2-D and 3-D modelling and inversion procedures for recovery of Earth conductivity are presented, emphasising the importance of updating model parameters using complementary geophysical data and rock physics relations. Requiring no specialist prior knowledge of electromagnetic theory, and providing a step-by-step guide through the necessary mathematics, this book provides an accessible introduction for advanced students, researchers and industry practitioners in exploration geoscience and petroleum engineering.

In the Fall of 1988, 64 geologists and geophysicists from 11 countries met in Killarney, Ontario, on the north shore of Lake Huron to examine evidence that suggests that the continental crust is exposed in cross-section at several key locations on the Earth's surface. The meeting, which was held under NATO auspices as an Advanced Study Institute, was a landmark event in that it was the first time that many of the lead scientists working on these complexes in relative isolation around the world had' ever gathered together to compare results. The present volume is a compendium of the invited lectures given on the principle sections, plus an array of supporting papers on these and other sections as well as on related topics such as crustal emplacement mechanisms, deformation and rheology. Nearly all of the best known sections are represented, including the Ivrea Zone, Calabria, the Kapuskasing Zone, Fiordland and many others. It is our hope that this Volume will serve as a reference for Earth scientists who are trying to understand levels of the crust not normally exposed to view, as well as a point of departure for new research and a teaching aid to new entrants in this relatively new field of study.

This research monograph presents all the branches of geophysics based on natural electromagnetic fields and their associated subjects. Meant for postgraduate and research level courses, it includes research guidance and collection of magnetotelluric data in some parts of Eastern India and their qualitative and quantitative interpretation. Specific topics highlighted include (i) Electrotellurics, (ii) Magnetotellurics, (iii) Geomagnetic Depth Sounding and Magnetometer Array Studies, (iv) Audio Frequency Magnetotellurics and Magnetic Methods, (v) Marine Magnetotelluric and Marine Controlled Source Electromagnetic Methods, (vi) Electrical Conductivity of Rocks and Minerals and (vii) Mathematical Modelling and Some Topics on Inversion needed for Interpretation of Geoelectrical Data.

The book deals primarily with the aspects like energy resources and its proper utilization, disposal of various forms of wastes and its effects and effects of major catastrophic events like nuclear disasters, global warming, etc. It also deals with the choice of suitable disposal sites for solid and hazardous waste, which is growing at an extremely rapid pace due to rapid industrialization, population growth (primarily in countries like India and China) and urbanization. In addition groundwater contamination due to various causes and its effect on the food chain is also amply discussed. The book is specifically aimed with the state-of-art information regarding research and development in these areas of study, coupled to extensive modelling and case based results obtained, both from India as well as other countries. The book is extremely instructive for the students, research workers, scientists, faculty members in Applied Physics, Solid Earth Geophysics, Radiometric Methods and Exploration, Ground Water Geochemistry, Mathematical Modeling Techniques in Earth Sciences, Near Surface Geophysics and Earth and Environmental Sciences.

This ground-breaking work is the first to cover the fundamentals of hydrogeophysics from both the hydrogeological and geophysical perspectives. Authored by leading experts and expert groups, the book starts out by explaining the fundamentals of hydrological characterization, with focus on hydrological data acquisition and measurement analysis as well as geostatistical approaches. The fundamentals of geophysical characterization are then at length, including the geophysical techniques that are often used for hydrogeological characterization. Unlike other books, the geophysical methods and petrophysical discussions presented here emphasize the theory, assumptions, approaches, and interpretations that are particularly important for hydrogeological applications. A series of hydrogeophysical case studies illustrate hydrogeophysical approaches for mapping hydrological units, estimation of hydrogeological parameters, and monitoring of hydrogeological processes. Finally, the book concludes with hydrogeophysical frontiers, i.e. on emerging technologies and stochastic hydrogeophysical inversion approaches.

This book introduces the principles of gravitational, magnetic, electrostatic, direct current electrical and electromagnetic fields, with detailed solutions of Laplace and electromagnetic wave equations by the method of separation of variables. Discussion includes behaviours of the scalar and vector potential and the nature of the solutions of these boundary value problems, along with the use of complex variables and conformal transformation, Green's theorem, Green's formula and Green's functions.