Introduction to Geophysics

Global Physical Fields and Processes in the Earth

verfasst von: Christoph Clauser

Verlag: Springer International Publishing

Buchreihe : Springer Textbooks in Earth Sciences, Geography and Environment

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This textbook on geophysics is a translated and revised editon from its third German edition Einführung in die Geophysik - Globale physikalische Felder und Prozesse in der Erde. Explaining the technical terminology, it introduces students and the interested scientific public to the physics of the Earth at an intermediate level. In doing so, it goes far beyond a purely phenomenological description, but systematically explains the physical principles of the processes and fields which affect the entire Earth: Its position in space; its internal structure; its age and that of its rocks; earthquakes and how they are used in exploring Earth’s structure; its shape, tides, and isostatic equilibrium; Earth's magnetic field, the geodynamo that generates it, and the interaction between the Earth's magnetosphere and the solar wind's plasma flow; the Earth's temperature field and heat transport processes in the core, mantle, and crust of the Earth and their role indriving the geodynamo and plate tectonics.

All chapters begin with a brief historical outline describing the development of each branch of geophysics up to the recent past. Selected biographies illustrate the personal and social conditions under which groundbreaking results were achieved. Detailed mathematical derivations facilitate understanding. Exercises with worked-out results allow readers to test the gained understanding.

A detailed appendix contains a wealth of useful additional information such as a geological time table, general reference data, conversion factors, the latest values of the natural constants, vector and tensor calculus, and two chapters on the basic equations of hydrodynamics and hydrothermics.

The book addresses bachelor and master students of geophysics and general earth science, as well as students of physics, engineering, and environmental sciences with geophysics as a minor subject.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Fundamentals of Geophysics, the Earth in the Universe, Its Material Composition, and Its Internal Structure

Abstract

This book discusses how—by analysis of the physical fields and processes within and on the Earth—we learn how old the Earth is, what are its internal structure and shape, and what are the causes and properties of its magnetic and temperature fields. In contrast, the geophysical survey methods for characterizing the upper crust which are used to explore for mineral ore deposits and hydrocarbon reservoirs are not treated in this book; specialized textbooks should be consulted for these.

Christoph Clauser

Chapter 2. Radioactive Decay and Rock Ages

Abstract

The question of the age of the Earth and the Universe was long the subject of contentious discussion. Towards the end of the eighteenth century, it began to be recognized that undisturbed sediment layers represent a time sequence. The significance of fossils for the identification of layers of the same age was also understood. However, it was Darwin’s evolution theory on the development of species that led to the linking of the relationship between species development and the chronostratigraphic succession of sedimentary rocks. Nevertheless, Darwin’s evolution theory only provided a very vague understanding of the necessary time spans. But it was only after the discovery of radioactivity that rocks could be dated by radioactive decay clocks. This chapter discusses a selection of such radiometric methods suitable for dating rocks in a great spectrum of different ages.

Christoph Clauser

Chapter 3. Earthquakes and Earth’s Structure

Abstract

Most of what we know about the structure of the Earth has been learned from the observation and interpretation of the propagation of seismic waves, In geophysics, we distinguish between seismology and exploration seismics: While in seismology information on the structure of the Earth is derived from earthquakes and the natural oscillations of the Earth excited by strong earthquakes, exploration seismics uses man-made vibrations (e.g., from explosions, vibrators, air guns, dropping weights, hammers) and natural microtremors to explore the upper crust for structures characteristic of deposits and reservoirs, especially of hydrocarbons. While exploration seismics has historically evolved from seismology and even today the two fields are strongly interconnected, we will not discuss them further here. Interested readers are referred to the numerous specialized texts that deal with the exploration methods of applied geophysics.

Christoph Clauser

Chapter 4. Gravity Field and Figure of the Earth

Abstract

The shape of the Earth has always been a question of importance to humanity, with philosophical and religious aspects as well as practical ones, especially for the early seafarers. Today, the figure of the Earth is determined with high accuracy using gravity measurements from space and on Earth. Such measurements also indicate local and temporal variations of gravity on Earth in space and time. These allow conclusions to be drawn about variations in the density and structure of the deep subsurface and about geodynamic processes.

Christoph Clauser

Chapter 5. Earth's Magnetic Field and Magnetosphere

Abstract

Magnetism is one of the longest known physical phenomena and the Earth's magnetic field was one of the first scientifically studied aspects. The magnetic needle and its directional property is reported to have been discovered in China in the twenty-sixth century BCE; however, other reports give its introduction by Arabs or Europeans in the thirteenth century CE. Greek philosophers wrote about the mineral magnetite in about 800 BCE. Today, we understand how Earth's magnetic field is generated by the geodynamo process in its core. The interaction of Earth's magnetic field with the solar wind and the interplanetary magnetic field drives electric current systems in the ionosphere and magnetosphere. These have implications for technical and, in particular, communications infrastructure, spacecraft safety, and the health of space and aviation personnel. The sudy of rock magnetism showed that Earth's magnetic field has changed its orientation several times in the past and that. Paleomagnetic methods also laid the foundation for the development of plate tectonics, i.e. the continental drift since the geological past until today.

Christoph Clauser

Chapter 6. Earth’s Heat and Temperature Field

Abstract

The heat stored in the Earth provides the energy which drives the thermal convection caused by thermal buoyancy in the Earth’s liquid outer core and plastic mantle. It is thus one of the main driving forces for the Earth's geodynamics and magnetic field. At the same time, geothermal energy stored in the Earth's crust at depths that can be drilled is a hitherto underutilized source of carbon dioxide-free heat and electrical energy. Exploration of Earth's thermal field requires drilling and, unlike the other geophysical fields, cannot be explored from the Earth's surface, at least not at present. The thermal field is also very sensitive to fluid flow when heat advection dominates heat conduction. This enables flow determination by thermal methods.

Christoph Clauser

Chapter 7. Appendix

Abstract

The appendix contains geological time tables for the Phanerozoic and Precambrian, a periodic table of the chemical elements, the base units of the SI system and conversion factors of other units into the SI system, current values of some physical natural constants, dimensions and characteristics of the Earth, mechanical and thermal properties of the Earth as a function of radius resp. of depth, notes on the representation and naming of large and small numerical values, computational rules for vectors, tensors, and the error function, an introduction to the Legendre transformation, the EMS-98 seismic intensity scale, formulas for the response function of a seismometer, an explanation of the magnetic α-effect, and basic equations of hydrodynamics and hydrothermics.

Christoph Clauser

Chapter 8. Answers to the Exercises

Abstract

This chapter contains worked out solutions and answers to all exercises and questions at the end of each chapter.This chapter contains worked out solutions and answers to all exercises and questions at the end of each chapter.

Christoph Clauser

Backmatter

Titel: Introduction to Geophysics
verfasst von: Christoph Clauser
Verlag: Springer International Publishing
Electronic ISBN: 978-3-031-17867-2
Print ISBN: 978-3-031-17866-5
DOI: https://doi.org/10.1007/978-3-031-17867-2