Geophysics

From Citizendium, the Citizens' Compendium

Geophysics is the study of the earth by quantitative physical methods, namely seismic, magnetic, electrical, electromagnetic, thermal and radioactivity methods.

It includes the branches of:

• Seismology [r]: Add brief definition or description (earthquakes and elastic waves)
• Gravity [r]: The tendency of objects with mass to accelerate toward each other. [e] (Earth's gravitational field)
• Geodesy [r]: Add brief definition or description (size and shape of the earth)
• Geomagnetism [r]: Add brief definition or description (including ionosphere, magnetosphere, Van Allen belts)
• Geoelectricity [r]: Add brief definition or description and electromagnetic methods (telluric currents, resistivity and conductivity structure, ground penetrating radar (GPR))
• Geothermometry [r]: Add brief definition or description (heat from internal processes, radioactivity, heat flow, volcanology, and hot springs)
• Hydrology [r]: The interdisciplinary study of the movement, characteristics and distribution of water, surface-water (fresh water and salt water), groundwater, and water-quality. [e] (ground and surface water, sometimes including glaciology)
• Physical oceanography [r]: The study of physical processes in the oceans. Topics include currents, tides, large scale ocean circulation and the formation of different water masses, and air-sea interactions such as the generation of surface waves by the wind. [e]
• Tectonophysics [r]: Add brief definition or description (geological processes in the earth)
• Exploration, engineering, and environmental geophysics [r]: Add brief definition or description
• Geophysical Engineering [r]: Add brief definition or description
• Glaciology [r]: Add brief definition or description
• Mineral Physics [r]: Add brief definition or description
• Engineering geology [r]: Add brief definition or description
• Geophysical MASINT [r]: A branch of measurement and signature intelligence that involves phenomena transmitted through the earth (ground, water, atmosphere) and manmade structures including emitted or reflected sounds, pressure waves, vibrations, and magnetic field or ionosphere disturbances. [e]

See also

• Fluid dynamics
• Society of Exploration Geophysicists
• American Geophysical Union
• National technical means of verification [r]: Euphemism principally for imagery intelligence satellites and other means of strategic arms control verification, principally because the Soviet Union did not want its public to know that they could not prevent Western observation of the state [e]

External links

• USGS Geomagnetism Program
• Case studies from TerraDat Geophysics documenting the use in shallow engineering and environmental applications
• Center for Gravity, Electrical, and Magnetic Studies

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