Geophysics

Geophysics, a major discipline of the Earth sciences and a sub discipline of physics, is the study of the whole Earth by the quantitative observation of its physical properties. Geophysical data are used in academics to observe tectonic plate motions, study the internal structure of the Earth, supplement data provided by geologic maps, and to non-destructively observe shallow deposits of oil. Geophysical survey data are used to analyze potential petroleum reservoirs and mineral deposits, to locate groundwater, to locate archaeological finds, to find the thicknesses of glaciers and soils, and for environmental remediation. The theories and techniques of geophysics are employed extensively in the planetary sciences in general.

Fields and related disciplines

Fields

• Geodesy,^[1] measurement of the Earth: GPS, vertical and horizontal motions of the Earth's surface, navigation, the study of the Earth's gravitational field, and the size and form of the Earth
• The study of large-scale motions of the Earth's surface and interior, including:

• Tectonophysics, the study of the physical processes that cause and result from plate tectonics
• Geodynamics, the study of modes of transport deformation within the Earth: rock deformation, mantle flow and convection, heat flow, lithosphere dynamics
• Seismology, the study of earthquakes and the propagation of elastic waves through the Earth

• Most of our knowledge of the Structure of the Earth is derived from seismology
• Shallow seismology is used in exploration geophysics (to find oil and gas) and for environmental characterization of the subsurface

• Geomagnetism, the study of the Earth's magnetic field, including its origin, telluric currents driven by the magnetic field, the Van Allen belts, and the interaction between the magnetosphere and the solar wind. This field is associated with paleomagnetism, or the measurement of the orientation of the Earth's magnetic field over the geologic past.
• Mathematical Geophysics, The development and applications of mathematical methods ^[2] and techniques for the solution of geophysical problems.^[3]
• Geophysical surveying:

• Exploration and engineering geophysics, using surface methods to detect or infer the presence and position of concentrations of ore minerals and hydrocarbons
• Archaeological geophysics, for archaeological imaging or mapping
• Environmental and Engineering Geophysics, for locating underground storage tanks (USTs) or utilities, Unexploded ordnance (UXO), delineating landfills, locating voids or potential subsidence, finding depth to, P-wave or S-wave velocity of, or rippability of bedrock, or the pathway of groundwater movement

Related Disciplines

• Volcanology, the study of volcanoes, volcanic features (hot springs, geysers, fumaroles), volcanic rock, and heat flow related to volcanoes
• Atmospheric sciences, which includes:

• Atmospheric electricity and the ionosphere
• Aeronomy, the study of the physical structure and chemistry of the atmosphere.
• Meteorology and Climatology, which both involve studies of the weather.

• The study of water on the Earth, hydrology, physical oceanography and glaciology
• Geological and geophysical engineering and Engineering geology, applying geophysics to the engineering design of facilities including roads, tunnels, and mines
• The study of the rocks and minerals, including petrophysics and aspects of mineralogy such as physical mineralogy and crystal structure

History of geophysics

The development of geophysics has been motivated by many theoretical and practical issues.

The term of geophysics was probably first used in Germany, where it appeared in scientific writings of the mid-19th century. The word geophysics was first used by Fröbel^[4][5] as "geophysik" in 1834.

See also

• American Geophysical Union
• Environmental and Engineering Geophysical Society
• European Geosciences Union
• Canadian Geophysical Union
• Royal Astronomical Society
• Society of Exploration Geophysicists (SEG)
• List of geophysicists
• Important publications in geophysics (geology)
• Important publications in geophysics (physics)
• List of free geophysics software
• Fluid dynamics
• Journal of Geophysics and Engineering

References

External links

• USGS Geomagnetism Program
• Case studies from TerraDat Geophysics documenting the use in shallow engineering and environmental applications
• Application of Geophysical Methods to Highway Related Problems