Geophysics, the study of the earth by quantitative physical methods, especially by seismic reflection and refraction, gravity, magnetic, electrical, electromagnetic, and radioactivity methods.
It includes the branches of:
- Seismology (earthquakes and elastic waves)
- Gravity and geodesy (the earth's gravitational field and the size and form of the earth)
- Atmospheric electricity and terrestrial magnetism (including ionosphere, Van Allen belts, telluric currents, etc.)
- Geothermometry (heating of the earth, heat flow, volcanology, and hot springs)
- Hydrology (ground and surface water, sometimes including glaciology)
- Physical oceanography
- Tectonophysics (geological processes in the earth)
- Exploration and engineering geophysics
A related field is geochemistry
Exploration geophysics is the use of seismic, gravity, magnetic, electrical and electromagnetic, etc., methods in the search for oil, gas, minerals, water, etc., with the objective of economic exploitation. The Society of Exploration Geophysicists (seg.org) has the most recent update of the sciences and technologies of exploration geophysics. (See also petroleum geology).