This volume combines review and solicited contributions, related to scientific studies of Division I of IAGA presented at its Scientific Assembly in Sopron in 2009. The book is aimed at intermediate to advanced readers dealing with the Earth’s magnetic field generation, its historical records in rocks and geological formations - including links to geodynamics and magnetic dating, with magnetic carriers in earth materials, electromagnetic induction and conductivity studies of the Earth interior with environmental applications of rock magnetism and electromagnetism. The aim of the book is to provide an overview of recent advances and future challenges in these particular fields of research.
This volume provides a comprehensive view on the different sources of the geomagnetic field both in the Earth’s interior and from the field’s interaction with the terrestrial atmosphere and the solar wind. It combines expertise from various relevant areas of geomagnetic and near Earth space research with the aim to better characterise the state and dynamics of Earth’s magnetic field. Advances in the exploitation of geomagnetic observations hold a huge potential not only for an improved quantitative description of the field source but also for a better understanding of the underlying processes and physics. Key is the separation of the field sources in the observations, especially, but not solely, during times of quiet geomagnetic conditions, when the most subtle geomagnetic effects can be identified and become significant. The collected articles are based on the current constellation of ground and space observations, and on state-of-the-art empirical models and physics-based simulations. Thus, it provides an in-depth overview over recent achievements, current limitations and challenges, and future opportunities in the field of geomagnetism and space sciences. Originally published in Space Science Reviews, Volume 206, Issue 1-4, March 2017
This is a discount Black and white version. Some images may be unclear, please see BCCampus website for the digital version.This book was born out of a 2014 meeting of earth science educators representing most of the universities and colleges in British Columbia, and nurtured by a widely shared frustration that many students are not thriving in courses because textbooks have become too expensive for them to buy. But the real inspiration comes from a fascination for the spectacular geology of western Canada and the many decades that the author spent exploring this region along with colleagues, students, family, and friends. My goal has been to provide an accessible and comprehensive guide to the important topics of geology, richly illustrated with examples from western Canada. Although this text is intended to complement a typical first-year course in physical geology, its contents could be applied to numerous other related courses.
This volume provides a comprehensive view on the different sources of the geomagnetic field both in the Earth’s interior and from the field’s interaction with the terrestrial atmosphere and the solar wind. It combines expertise from various relevant areas of geomagnetic and near Earth space research with the aim to better characterise the state and dynamics of Earth’s magnetic field. Advances in the exploitation of geomagnetic observations hold a huge potential not only for an improved quantitative description of the field source but also for a better understanding of the underlying processes and physics. Key is the separation of the field sources in the observations, especially, but not solely, during times of quiet geomagnetic conditions, when the most subtle geomagnetic effects can be identified and become significant. The collected articles are based on the current constellation of ground and space observations, and on state-of-the-art empirical models and physics-based simulations. Thus, it provides an in-depth overview over recent achievements, current limitations and challenges, and future opportunities in the field of geomagnetism and space sciences. Originally published in Space Science Reviews, Volume 206, Issue 1-4, March 2017
The Old Theory Until now, there was only one theory regarding the source of Earth's magnetic field, which is the internal dynamo theory. This theory was accepted because it offered the best explanation at the time. Also, much research has been done to support the theory. According to the internal dynamo theory, a dynamo near the center of the planet generates the current that produces the magnetic field. This dynamo would be in the liquid outer core of the planet. It would produce the magnetic axis and project it from the planet. The axis would expand and spread the magnetic field around the planet. This theory also suggests that the internal dynamo is sustaining itself by using fuel from Earth's core. The internal dynamo theory has changed over the years. At first scientists thought that a bar magnet was in the center of the planet and the compass needle pointed to the poles of that magnet. This made perfect sense at the time because we can see that the same thing happens when we put a compass near a bar magnet. The Bar Magnet In The Sun image demonstrates the idea of the bar magnet theory. However, this example shows the bar magnet imbedded within the sun because just like the planets, the sun also has a magnetic field, which is more complex than Earth's magnetic field. Scientists have tried to use the internal dynamo theory to explain the magnetic fields of all the planets, some moons, and the sun. However, the old model does not work for the sun, moon, and other planets. The bar magnet concept lasted a long time as the main theory regarding the source of Earth's magnetic field. However, while trying to apply it to other cases, scientists found problems with the theory. Over the years, they discovered that a bar magnet could not hold magnetism above the temperature of 770 degrees centigrade because high heat destroys magnetism. This caused the theory to gradually evolve over time.
Developed by three experts to coincide with geology lab kits, this laboratory manual provides a clear and cohesive introduction to the field of geology. Introductory Geology is designed to ease new students into the often complex topics of physical geology and the study of our planet and its makeup. This text introduces readers to the various uses of the scientific method in geological terms. Readers will encounter a comprehensive yet straightforward style and flow as they journey through this text. They will understand the various spheres of geology and begin to master geological outcomes which derive from a growing knowledge of the tools and subjects which this text covers in great detail.
Electromagnetism and the Earth's Interior reviews the earth's magnetic fields in terms of physical processes that are occurring in the earth's interior. The book describes the distribution of the earth's magnetic field in terms of declination, horizontal intensity, and vertical intensity. The dynamo theory concerns the self-exciting electric generation in the interior of the earth, and can account for any geomagnetic secular variation. A workable laboratory model—a dynamo mechanism of Lowes and Wilkinson (1963) has a significant role on the dynamo theory for the model actually demonstrated Herzenberg's proof that was developed mathematically. The text also describes various aspects of long-term geomagnetic variations, such as the decrease in the dipole moment, the reversal of the geomagnetic field, the drift of eccentric dipole, the fluctuation in the length of day, and the geomagnetic secular variation. The book also investigates the possible effects of the ocean on geomagnetic variations. The characteristics of transient geomagnetic variations on islands can point to a possible special underground structure. The book is suitable for geologists, astrophysicists, seismologists, and students of the natural sciences.
Topics involved in studies of the Earth's magnetic field and its secular variation range from the intricate observations of geomagnetism, to worldwide studies of archeomagnetism and paleomagnetism, through to the complex mathematics of dynamo theory. Traditionally these different aspects of geomagnetism have in the main been studied and presented in isolation from each other. This text draws together these lines of inquiry into an integrated framework to highlight the interrelationships and thus to provide a more comprehensive understanding of the geomagnetic field.
