Electromagnetic Methods in Geophysics

Theoretical basis and practical aspects of the environmental, engineering, geologic, archaeologic, mining, and small to large scale area mapping applications discussed in context of various electromagnetic methods

The shallow part of the subsoil, either natural as well as urban or industrial, is impacted by a large number of interactions and interferences on a daily basis, worldwide, because of anthropogenic activities. Excavations, trenching and digging for building constructions, road maintenance, archaeological, urban development, forensic, cavity search, ore bodies search, geological, geotechnical and engineering purposes are conducted every day all over the world. The a-priori knowledge of the subsoil is often poor or non-existing, hence the need for (non-destructive) techniques for the enhancement of the model of the soil, prior to excavation.

There are several geophysical techniques whose deployment aims at defining such models, and many of them, for their implementation on site, makes use of sensors to be coupled with the soil (embedded, like geophones for seismic refraction and reflection, or electrodes for Electrical resistivity methods). One of the main advantages of the whole family of the Electromagnetic (EM) methods is because they do not make use of any embedded sensor, fixed on top of the soil surface. This makes the technique fast, non-destructive, and highly productive from the data acquisition point of view. The applicability of the "EM family" methods is rather wide, and ranges from utility mapping, to cavity detection, pollutants search, UXO search, Volcanogenic Massive Sulphides (VMS) search, geotechnical engineering applications and so on. The dimension of the areas that can be covered varies from a few squared meters, for detailed studies with high resolution, to thousands of squared meters for exploration that can reach down to hundreds of meters in depth (for Airborne EM Techniques) for the search of targets of a larger size.

Electromagnetic Methods in Geophysics: Theory and Applications provides a general introduction to the electromagnetic methods in several application fields. Physical and mathematical principles and fields of applications are well-explained, and the field acquisition procedures, data processing and interpretation, are illustrated to guarantee the best understanding of the results, on a layman perspective.

Volume highlights include:

- Detailed fundamentals of the theory behind each of the electromagnetic techniques in engineering geophysics, and the practical details of real case studies, highlighting possible benefit and actual results
- Discusses practical and logistics aspect linked to project optimization, and practical valuable details including survey planning and logistics connected to the shipping of instrumentations worldwide
- Illustrates many actual case studies from small to large scale, in concrete scanning, utility mapping, archaeology, geotechnical study, ore search- Involves technically feasible, and economically valuable projects, that require the optimization of cost associated to planning and execution of a survey
- Introduction of new suggestions for better data acquisition, processing and interpretation
- Illustrates examples of applications from shallow, sub-centimeters resolution cases to deep, large scale study
- Useful guide for all those who approach these methods for the first time since the volume widely demonstrates that there is no need for extensive math skills for a general understanding of electromagnetic methods
- Assesses the scope and importance of the advanced techniques of analysis without entering into the details of their implementation
- Proposes examples from unpublished case historyies in which electromagnetic methods are applied in several fields such as archaeology, engineering, environmental, geotechnical, monumental heritage diagnosis, etc.
- Electromagnetic methods potential are manifold for e.g., they aid the location and recovery of archaeological structures, as they can, non-invasively, very rapidly survey extensive areas, and through the use of these examples, it is understood how to design and perform an electromagnetic survey for a specific purpose
- Most innovative data acquisition and processing systems are described that enable rapid reconnaissance of the surface sub-levels of the earth, even over areas of considerable extension, yielding highly detailed evidence, even in very challenging cases
- Serves useful as a reference volume for students in geophysics, architecture, engineering, archaeology, etc. and as practical guidebook for professionals, with potential readers wide and diversified from academic to industry professionals and government agencies