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Geomagnetists measure the present magnetic field and its short-term
changes through a global network of permanent geomagnetic observatories
as well as from satellite surveys. Together with measurements taken over
the past few centuries these data are important for devising models to
describe the geomagnetic field and explain its origin. Sophisticated supercomputer
simulations of the geodynamo have been able to replicate its dominant features
and some of its long-term behavior.
Magnetic anomalies in the geomagnetic field provide important information for understanding the structure of the oceanic and continental crust. Oceanic magnetic anomalies provided the key to sea-floor spreading, which played a key role in deciphering plate tectonic motions. Continental magnetic surveys are important for locating mineral resources of commercial importance. Aeromagnetic surveys in Antarctica contribute to understanding the geology, lithospheric structure, and tectonic evolution below the ice.
Paleomagnetists interpret fossil magnetizations in rocks and
sediments from the continents and oceans. These natural archives hold a
record of the geomagnetic field in the geological past, and shed light
on the motions of the continents. The paleomagnetic record also reveals
the history of numerous reversals of polarity that Earth's magnetic field
has undergone throughout geologic time.
Rock magnetists study the physics and chemistry of magnetic minerals, with particular emphasis on how they are formed and become magnetized. This knowledge forms the basis of paleomagnetic studies. It has been applied in recent years to understanding environmental problems and ancient climatic conditions.
Electromagnetists, by studying the induction of electric currents in the earth induced by electromagnetic waves from ionospheric disturbances, time-varying magnetospheric fields and world-wide thunderstorm activity, delineate electrical conductivity structures deep within the planet related to variations in composition, temperature, and other properties.
The members of the GP section represent a variety of scientific backgrounds, including applied mathematics, physics and geology. They are linked by their common interest in the Earth's magnetic field and how its characteristics can be used to understand Earth's structure, dynamics, and history.