Outline of geophysics
Encyclopedia
The following outline is provided as an overview of and topical guide to geophysics:
Geophysics
– the physics of the Earth
and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological
applications: Earth's shape
; its gravitational and magnetic fields
; its internal structure
and composition; its dynamics
and their surface expression in plate tectonics
, the generation of magmas, volcanism
and rock formation. However, modern geophysics organizations have a broader definition that includes the hydrological cycle including snow
and ice
; fluid dynamics
of the oceans and the atmosphere
; electricity
and magnetism
in the ionosphere
and magnetosphere
and solar-terrestrial relations; and analogous problems associated with the Moon
and other planets.
Geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
– the physics of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
applications: Earth's shape
Figure of the Earth
The expression figure of the Earth has various meanings in geodesy according to the way it is used and the precision with which the Earth's size and shape is to be defined. The actual topographic surface is most apparent with its variety of land forms and water areas. This is, in fact, the surface...
; its gravitational and magnetic fields
Earth's magnetic field
Earth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...
; its internal structure
Structure of the Earth
The interior structure of the Earth, similar to the outer, is layered. These layers can be defined by either their chemical or their rheological properties. The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a...
and composition; its dynamics
Geodynamics
Geodynamics is a subfield of geophysics dealing with dynamics of the Earth. It applies physics, chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and geologic phenomena such as seafloor spreading, mountain building, volcanoes, earthquakes, faulting and...
and their surface expression in plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
, the generation of magmas, volcanism
Volcanism
Volcanism is the phenomenon connected with volcanoes and volcanic activity. It includes all phenomena resulting from and causing magma within the crust or mantle of a planet to rise through the crust and form volcanic rocks on the surface....
and rock formation. However, modern geophysics organizations have a broader definition that includes the hydrological cycle including snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
and ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
; fluid dynamics
Geophysical fluid dynamics
Geophysical fluid dynamics is the study of naturally occurring, large-scale flows on Earth and other planets. It is applied to the motion of fluids in the ocean and outer core, and to gases in the atmosphere of Earth and other planets...
of the oceans and the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
; electricity
Atmospheric electricity
Atmospheric electricity is the regular diurnal variations of the Earth's atmospheric electromagnetic network . The Earth's surface, the ionosphere, and the atmosphere is known as the global atmospheric electrical circuit...
and magnetism
Magnetism
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...
in the ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
and magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
and solar-terrestrial relations; and analogous problems associated with the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
and other planets.
Nature of geophysics
Geophysics can be described as all of the following:- An academic disciplineAcademic disciplineAn academic discipline, or field of study, is a branch of knowledge that is taught and researched at the college or university level. Disciplines are defined , and recognized by the academic journals in which research is published, and the learned societies and academic departments or faculties to...
: one with academic departments, curricula and degrees; national and international societies; and specialized journals. - A scientific field (a branch of scienceScienceScience is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
) – widely-recognized category of specialized expertise within science, and typically embodies its own terminology and nomenclature. Such a field will usually be represented by one or more scientific journals, where peer reviewed research is published. There are several geophysics-related scientific journals.- A natural scienceNatural scienceThe natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using empirical and scientific methods...
– one that seeks to elucidate the rules that govern the naturalNatureNature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...
world using empiricalEmpirical methodThe empirical method is generally taken to mean the approach of using a collection of data to base a theory or derive a conclusion in science...
and scientific methodScientific methodScientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...
s.- A physical sciencePhysical sciencePhysical science is an encompassing term for the branches of natural science and science that study non-living systems, in contrast to the life sciences...
– one that studies non-living systems.- An earth scienceEarth scienceEarth science is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences...
– one that studies the plant EarthEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
and its surroundings.
- An earth science
- A physical science
- A biological science – one that studies the effect of organisms on their physical environment.
- A natural science
- An interdisciplinary field – one that overlaps atmospheric sciencesAtmospheric sciencesAtmospheric sciences is an umbrella term for the study of the atmosphere, its processes, the effects other systems have on the atmosphere, and the effects of the atmosphere on these other systems. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather...
, geologyGeologyGeology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, glaciologyGlaciologyGlaciology Glaciology Glaciology (from Middle French dialect (Franco-Provençal): glace, "ice"; or Latin: glacies, "frost, ice"; and Greek: λόγος, logos, "speech" lit...
, hydrologyHydrologyHydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
, oceanographyOceanographyOceanography , also called oceanology or marine science, is the branch of Earth science that studies the ocean...
and physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
.
Branches of geophysics
- BiogeophysicsBiogeophysicsBiogeophysics is a subdiscipline of geophysics concerned with how plants, microbial activity and other organisms alter geologic materials and affect geophysical signatures.- See also :* Astrobiology* Biogeology* Exploration geophysics* Geomicrobiology...
– study of how plants, microbial activity and other organisms alter geologic materials and affect geophysical signatures. - Exploration geophysicsExploration geophysicsExploration geophysics is the applied branch of geophysics which uses surface methods to measure the physical properties of the subsurface Earth, in order to detect or infer the presence and position of ore minerals, hydrocarbons, geothermal reservoirs, groundwater reservoirs, and other geological...
– the use of surface methods to detect concentrations of oreOreAn ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
minerals and hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s. - Geophysical fluid dynamicsGeophysical fluid dynamicsGeophysical fluid dynamics is the study of naturally occurring, large-scale flows on Earth and other planets. It is applied to the motion of fluids in the ocean and outer core, and to gases in the atmosphere of Earth and other planets...
– study of naturally occurring, large-scale flows on EarthEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
and other planets. - GeodesyGeodesyGeodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...
– measurement and representation of the Earth, including its gravitational field. - GeodynamicsGeodynamicsGeodynamics is a subfield of geophysics dealing with dynamics of the Earth. It applies physics, chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and geologic phenomena such as seafloor spreading, mountain building, volcanoes, earthquakes, faulting and...
– study of modes of transport deformationDeformation (mechanics)Deformation in continuum mechanics is the transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body...
within the Earth: rock deformation, mantle convectionMantle convectionMantle convection is the slow creeping motion of Earth's rocky mantle caused by convection currents carrying heat from the interior of the Earth to the surface. The Earth's surface lithosphere, which rides atop the asthenosphere , is divided into a number of plates that are continuously being...
, heat flow, and lithosphere dynamics. - Geomagnetism – study of the Earth's magnetic fieldEarth's magnetic fieldEarth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...
, including its origin, telluric currentTelluric currentA telluric current , or Earth current, is an electric current which moves underground or through the sea. Telluric currents result from both natural causes and human activity, and the discrete currents interact in a complex pattern...
s driven by the magnetic field, the Van Allen beltsVan Allen radiation beltThe Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...
, and the interaction between the magnetosphereMagnetosphereA magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
and the solar windSolar windThe solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
. - Mathematical geophysicsMathematical geophysicsMathematical geophysics is concerned with developing mathematical methods for use in geophysics. As such, it has application in many fields in geophysics, particularly geodynamics and seismology.- Geophysical fluid dynamics :...
– development and applications of mathematical methods and techniques for the solution of geophysical problems. - Mineral physicsMineral physicsMineral physics is the science of materials that compose the interior of planets, particularly the Earth. It overlaps with petrophysics, which focuses on whole-rock properties...
– science of materials that compose the interior of planets, particularly the Earth. - Near-surface geophysicsNear-surface geophysicsNear-surface geophysics is the use of geophysical methods to investigate small-scale features in the shallow subsurface. It is closely related to applied geophysics or exploration geophysics. Methods used include seismic refraction and reflection, gravity, magnetic, electric, and electromagnetic...
– the use of geophysical methods to investigate small-scale features in the shallow (tens of meters) subsurface. - PaleomagnetismPaleomagnetismPaleomagnetism is the study of the record of the Earth's magnetic field in rocks. Certain minerals in rocks lock-in a record of the direction and intensity of the magnetic field when they form. This record provides information on the past behavior of Earth's magnetic field and the past location of...
– measurement of the orientation of the Earth's magnetic fieldEarth's magnetic fieldEarth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...
over the geologic past. - SeismologySeismologySeismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...
– study of the structure and composition of the Earth through seismic waveSeismic waveSeismic waves are waves of energy that travel through the earth, and are a result of an earthquake, explosion, or a volcano that imparts low-frequency acoustic energy. Many other natural and anthropogenic sources create low amplitude waves commonly referred to as ambient vibrations. Seismic waves...
s, and of surface deformations during earthquakeEarthquakeAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
s and seismic hazardSeismic hazardSeismic hazard refers to the study of expected earthquake ground motions at the earth's surface, and its likely effects on existing natural conditions and man-made structures for public safety considerations; the results of such studies are published as seismic hazard maps, which identify the...
s. - TectonophysicsTectonophysicsTectonophysics, a branch of geophysics, is the study of the physical processes that underlie tectonic deformation. The field encompasses the spatial patterns of stress, strain, and differing rheologies in the lithosphere and asthenosphere of the Earth; and the relationships between these patterns...
– study of the physical processes that cause and result from plate tectonics.
History of geophysics
- History of geomagnetismHistory of geomagnetismThe history of geomagnetism is concerned with the history of the study of Earth's magnetic field. It encompasses the history of navigation using compasses, studies of the prehistoric magnetic field , and applications to plate tectonics.Magnetism has been known since prehistory, but knowledge of the...
- Timeline of the development of tectonophysicsTimeline of the development of tectonophysicsThe evolution of tectonophysics is closely linked to the history of the continental drift and plate tectonics hypotheses. The continental drift hypothesis had many flaws and scarce data. The fixist, the contracting Earth and the expanding Earth concepts had many flaws as well. Wegener had data for...
- Vine-Matthews-Morley hypothesis
Gravity
- Bouguer anomalyBouguer anomalyIn geodesy and geophysics, the Bouguer anomaly is a gravity anomaly, corrected for the height at which it is measured and the attraction of terrain. The height correction alone gives a free-air anomaly.-Bouguer reduction:...
- GeoidGeoidThe geoid is that equipotential surface which would coincide exactly with the mean ocean surface of the Earth, if the oceans were in equilibrium, at rest , and extended through the continents . According to C.F...
- GeopotentialGeopotentialGeopotential is the potential of the Earth's gravity field. For convenience it is often defined as minus the potential energy per unit mass, so that the gravity vector is obtained as the gradient of this potential, without the minus....
- Gravity anomalyGravity anomalyA gravity anomaly is the difference between the observed acceleration of Earth's gravity and a value predicted from a model.-Geodesy and geophysics:...
- Undulation of the geoidUndulation of the geoidUndulation of the geoid is the mathematical process of determining the height in meters above the geoid from the height provided by the GPS system which uses the ellipsoid as reference...
Atmospheric electricity
- LightningLightningLightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
- Sprite (lightning)Sprite (lightning)Sprites are large-scale electrical discharges that occur high above thunderstorm clouds, or cumulonimbus, giving rise to a quite varied range of visual shapes flickering in the night sky. They are triggered by the discharges of positive lightning between an underlying thundercloud and the...
Electricity in Earth
- Electrical resistivity tomographyElectrical resistivity tomographyElectrical resistivity tomography or electrical resistivity imaging is a geophysical technique for imaging sub-surface structures from electrical measurements made at the surface, or by electrodes in one or more boreholes. It is closely related to the medical imaging technique electrical...
- Induced polarizationInduced polarizationInduced polarization is a geophysical imaging technique used to identify subsurface materials, such as ore. The method is similar to electrical resistivity tomography, in that an electric current is induced into the subsurface through two electrodes, and voltage is monitored through two other...
- Seismoelectrical methodSeismoelectrical MethodThe seismoelectrical method is based on the generation of electromagnetic fields in soils and rocks by seismic waves...
- Spectral induced polarisationSpectral Induced PolarisationSpectral induced polarisation or Complex resistivity is a geophysical survey technique and an extension of the induced polarisation method, being itself an extension of measuring the Earth's resistance at a single frequency or under direct current . SIP measures the frequency-dependent Spectral...
- Spontaneous potentialSpontaneous potentialSpontaneous potential , also called self potential, is a naturally occurring electric potential difference in the Earth, measured by an electrode relative to a fixed reference electrode...
- Telluric currentTelluric currentA telluric current , or Earth current, is an electric current which moves underground or through the sea. Telluric currents result from both natural causes and human activity, and the discrete currents interact in a complex pattern...
Electromagnetic waves
- Alfvén waveAlfvén waveAn Alfvén wave, named after Hannes Alfvén, is a type of magnetohydrodynamic wave.-Definition:An Alfvén wave in a plasma is a low-frequency travelling oscillation of the ions and the magnetic field...
- Dawn chorus (electromagnetic)Dawn chorus (electromagnetic)The electromagnetic dawn chorus is an unexplained phenomenon that occurs most often at sunrise or shortly after, that resembles the sound of the birds' dawn chorus. Chorus is believed to be generated by a Doppler-shifted cyclotron interaction between anisotropic distributions of energetic ...
- Hiss (electromagnetic)Hiss (electromagnetic)Electromagnetic hiss is a naturally occurring Extremely Low Frequency/Very Low Frequency electromagnetic wave that is generated in the plasma of either the Earth's ionosphere or magnetosphere...
- MagnetotelluricsMagnetotelluricsMagnetotellurics is an electromagnetic geophysical method of imaging the earth's subsurface by measuring natural variations of electrical and magnetic fields at the Earth's surface. Investigation depth ranges from 300m below ground by recording higher frequencies down to 10,000m or deeper with...
- Seismo-electromagneticsSeismo-electromagneticsSeismo-electromagnetics is the study of electromagnetic phenomena associated with seismic activity such as earthquakes and volcanos, and also the use of electromagnetic methods in seismology such as magnetotellurics. Links between the electromagnetic fields in the lithosphere and those in the...
- Transient electromagneticsTransient electromagneticsTransient electromagnetics, , is a geophysical exploration technique in which electric and magnetic fields are induced by transient pulses of electric current and the subsequent decay response measured...
- Whistler (radio)Whistler (radio)A whistler is a very low frequency electromagnetic wave which can be generated, for example, by lightning. Frequencies of terrestrial whistlers are 1 to 30 kHz, with maximum usually at 3 to 5 kHz. Although they are electromagnetic waves, they occur at audio frequencies, and can be...
Fluid dynamics
- IsostasyIsostasyIsostasy is a term used in geology to refer to the state of gravitational equilibrium between the earth's lithosphere and asthenosphere such that the tectonic plates "float" at an elevation which depends on their thickness and density. This concept is invoked to explain how different topographic...
- Post-glacial reboundPost-glacial reboundPost-glacial rebound is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostasy...
- Mantle convectionMantle convectionMantle convection is the slow creeping motion of Earth's rocky mantle caused by convection currents carrying heat from the interior of the Earth to the surface. The Earth's surface lithosphere, which rides atop the asthenosphere , is divided into a number of plates that are continuously being...
- Geodynamo
Geomagnetism subfields
- Environmental magnetismEnvironmental magnetismEnvironmental magnetism is the study of magnetism as it relates to the effects of climate, sediment transport, pollution and other environmental influences on magnetic minerals. It makes use of techniques from rock magnetism and magnetic mineralogy...
- MagnetostratigraphyMagnetostratigraphyMagnetostratigraphy is a geophysical correlation technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout the section. The samples are analyzed to determine their characteristic remanent magnetization , that is, the...
- PaleomagnetismPaleomagnetismPaleomagnetism is the study of the record of the Earth's magnetic field in rocks. Certain minerals in rocks lock-in a record of the direction and intensity of the magnetic field when they form. This record provides information on the past behavior of Earth's magnetic field and the past location of...
- Rock magnetismRock magnetismRock magnetism is the study of the magnetic properties of rocks, sediments and soils. The field arose out of the need in paleomagnetism to understand how rocks record the Earth's magnetic field. This remanence is carried by minerals, particularly certain strongly magnetic minerals like magnetite...
Description
- Geomagnetic poleGeomagnetic poleThe geomagnetic poles are antipodal points where the axis of a theoretical dipole intersects the Earth's surface. This dipole is equivalent to a powerful bar magnet at the center of the Earth, and it is the dipole that comes closest to accounting for the magnetic field observed at the Earth's...
- Magnetic declinationMagnetic declinationMagnetic declination is the angle between magnetic north and true north. The declination is positive when the magnetic north is east of true north. The term magnetic variation is a synonym, and is more often used in navigation...
- Magnetic inclination
- North Magnetic PoleNorth Magnetic PoleThe Earth's North Magnetic Pole is the point on the surface of the Northern Hemisphere at which the Earth's magnetic field points vertically downwards . Though geographically in the north, it is, by the direction of the magnetic field lines, physically the south pole of the Earth's magnetic field...
- South Magnetic PoleSouth Magnetic PoleThe Earth's South Magnetic Pole is the wandering point on the Earth's surface where the geomagnetic field lines are directed vertically upwards...
Short-term changes
- Secular variationSecular variationThe secular variation of a time series is its long-term non-periodic variation . Whether something is perceived as a secular variation or not depends on the available timescale: a secular variation over a time scale of centuries may be part of a periodic variation over a time scale of millions of...
- Geomagnetic secular variation
- Geomagnetic jerkGeomagnetic jerkIn geophysics, a geomagnetic jerk or secular geomagnetic variation impulse is a relatively sudden change in the second derivative of the Earth's magnetic field with respect to time....
Long term behavior
- Apparent polar wanderApparent polar wanderApparent polar wander is the imaginary movement of the Earth's magnetic poles relative to a continent while regarding the continent being studied as fixed in position, as determined by paleomagnetic data...
- Geomagnetic excursionGeomagnetic excursionA geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth's magnetic field. Unlike reversals however, an excursion does not permanently change the large scale orientation of the field, but rather represents a dramatic, typically short-lived decrease in field...
- Geomagnetic poleGeomagnetic poleThe geomagnetic poles are antipodal points where the axis of a theoretical dipole intersects the Earth's surface. This dipole is equivalent to a powerful bar magnet at the center of the Earth, and it is the dipole that comes closest to accounting for the magnetic field observed at the Earth's...
- Geomagnetic reversalGeomagnetic reversalA geomagnetic reversal is a change in the Earth's magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth's field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse...
- Geomagnetic secular variation
- Polar wanderPolar wanderPolar wander is the movement of the North and South Poles of the Earth with respect to the continents. This motion can be divided into two components: that due to continental drift , and true polar wander, in which the mantle and the crust rotate together into new orientations....
- True polar wanderTrue polar wanderTrue polar wander is a solid-body rotation of a planet or moon with respect to its spin axis, causing the geographic locations of the North and South Poles to change, or "wander". In a stable state, the largest moments of inertia axis is aligned with the spin axis, with the smaller two moment of...
Magnetostratigraphy
- Archaeomagnetic datingArchaeomagnetic datingArchaeomagnetic dating is the study and interpretation of the signatures of the Earth's magnetic field at past times recorded in archaeological materials. These paleomagnetic signatures are fixed when ferromagnetic materials such as magnetite cool below the Curie point, freezing the magnetic moment...
- Chron
- MagnetostratigraphyMagnetostratigraphyMagnetostratigraphy is a geophysical correlation technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout the section. The samples are analyzed to determine their characteristic remanent magnetization , that is, the...
- Superchron (currently redirected to Geomagnetic reversal#Moyero Reversed Superchron)
Rock magnetism
- Magnetic mineralogyMagnetic mineralogyMagnetic mineralogy is the study of the magnetic properties of minerals. The contribution of a mineral to the total magnetism of a rock depends strongly on the type of magnetic order or disorder. Magnetically disordered minerals contribute a weak magnetism and have no remanence...
- Natural remanent magnetizationNatural Remanent MagnetizationNatural remanent magnetization is the permanent magnetism of a rock or sediment. In some forms, it can preserve a record of the Earth's field and the tectonic movement of the rock over millions of years...
- Saturation isothermal remanence
- Thermoremanent magnetizationThermoremanent magnetizationWhen an igneous rock cools, it acquires a thermoremanent magnetization from the Earth's field. TRM can be much larger than it would be if exposed to the same field at room temperature . This remanence can also be very stable, lasting without significant change for millions of years...
- Viscous remanent magnetizationViscous Remanent MagnetizationViscous remanent magnetization , also known as viscous magnetization, is remanence that is acquired by ferromagnetic materials by sitting in a magnetic field for some time. The natural remanent magnetization of an igneous rock can be altered by this process...
Magnetic survey
- Aeromagnetic surveyAeromagnetic surveyAn aeromagnetic survey is a common type of geophysical survey carried out using a magnetometer aboard or towed behind an aircraft. The principle is similar to a magnetic survey carried out with a hand-held magnetometer, but allows much larger areas of the Earth's surface to be covered quickly for...
- Geophysical surveyGeophysical surveyGeophysical survey is the systematic collection of geophysical data for spatial studies. Geophysical surveys may use a great variety of sensing instruments, and data may be collected from above or below the Earth's surface or from aerial or marine platforms. Geophysical surveys have many...
- Magnetic survey (archaeology)Magnetic survey (archaeology)Magnetic survey is one of a number of methods used in archaeological geophysics. Magnetic surveys record spatial variation in the Earth's magnetic field. In archaeology, magnetic surveys are used to detect and map archaeological artifacts and features...
- MagnetometerMagnetometerA magnetometer is a measuring instrument used to measure the strength or direction of a magnetic field either produced in the laboratory or existing in nature...
Mineral physics
- CreepCreep (deformation)In materials science, creep is the tendency of a solid material to slowly move or deform permanently under the influence of stresses. It occurs as a result of long term exposure to high levels of stress that are below the yield strength of the material....
- ElasticityElasticity (physics)In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
- MeltingMeltingMelting, or fusion, is a physical process that results in the phase change of a substance from a solid to a liquid. The internal energy of a substance is increased, typically by the application of heat or pressure, resulting in a rise of its temperature to the melting point, at which the rigid...
- Rheology
- Thermal expansionThermal expansionThermal expansion is the tendency of matter to change in volume in response to a change in temperature.When a substance is heated, its particles begin moving more and thus usually maintain a greater average separation. Materials which contract with increasing temperature are rare; this effect is...
- ViscosityViscosityViscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
Vibration
- EarthquakeEarthquakeAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
– a motion that causes seismic waves. - AftershockAftershockAn aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
– follows larger earthquake. - Blind thrustBlind thrust earthquakeA blind thrust earthquake is an earthquake along a thrust fault that does not show signs on the Earth's surface, hence the designation "blind" . Such faults, being invisible at the surface, have not been mapped by standard surface geological mapping...
– along a thrust fault that does not show on the Earth's surface. - ForeshockForeshockA foreshock is an earthquake that occurs before a larger seismic event and is related to it in both time and space. The designation of an earthquake as foreshock, mainshock or aftershock is only possible after the event....
– precedes larger earthquake. - Harmonic tremorHarmonic tremorHarmonic tremor describes a long-duration release of seismic energy, with distinct spectral lines, that often precedes or accompanies a volcanic eruption...
– long-duration, with distinct frequencies, associated with a volcanic eruption. - InterplateInterplate earthquakeAn interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other...
– at the boundary between two tectonic plates. - IntraplateIntraplate earthquakeAn intraplate earthquake is an earthquake that occurs in the interior of a tectonic plate, whereas an interplate earthquake is one that occurs at a plate boundary....
– in the interior of a tectonic plate. - MegathrustMegathrust earthquakeMegathrust earthquakes occur at subduction zones at destructive plate boundaries , where one tectonic plate is forced under another. Due to the shallow dip of the plate boundary, which causes large sections to get stuck, these earthquakes are among the world's largest, with moment magnitudes ...
– at subduction zones - Remotely triggered earthquakesRemotely triggered earthquakesRemotely triggered earthquakes have also been characterized as "the very long reach of very large earthquakes." Fundamentally, it is postulated that large earthquakes can have an influence outside of the immediate aftershock zone, and actually activate other earthquakes at considerable distance...
– after main shock but outside the aftershock zone. - SlowSlow earthquakeA slow earthquake is a discontinuous, earthquake-like event that releases energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake...
– over a period of hours to months. - SubmarineSubmarine earthquakeA submarine, undersea, or underwater earthquake is an earthquake that occurs underwater at the bottom of a body of water, especially an ocean. They are the leading cause of tsunamis...
– under a body of water. - SupershearSupershear earthquakeA supershear earthquake is an earthquake in which the propagation of the rupture along the fault surface occurs at speeds in excess of the seismic shear wave velocity. This causes a form of sonic boom to occur.-Rupture propagation velocity:...
– rupture propagates faster than seismic shear wave velocity. - TsunamiTsunami earthquakeA tsunami earthquake is an earthquake that triggers a tsunami of a magnitude that is very much larger than the magnitude of the earthquake as measured by shorter-period seismic waves. The term was introduced by Hiroo Kanamori in 1972. Such events are a result of relatively slow rupture velocities...
– triggers a tsunamiTsunamiA tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
. - Seismic waves
- PP-waveP-waves are a type of elastic wave, also called seismic waves, that can travel through gases , solids and liquids, including the Earth. P-waves are produced by earthquakes and recorded by seismographs...
- SS-waveA type of seismic wave, the S-wave, secondary wave, or shear wave is one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves....
- SurfaceSurface waveIn physics, a surface wave is a mechanical wave that propagates along the interface between differing media, usually two fluids with different densities. A surface wave can also be an electromagnetic wave guided by a refractive index gradient...
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- LoveLove waveIn elastodynamics, Love waves are horizontally polarized shear waves guided by an elastic layer, which is "welded" to an elastic half space on one side while bordering a vacuum on the other side...
- RaleighRayleigh waveRayleigh waves are a type of surface acoustic wave that travels on solids. They are produced on the Earth by earthquakes, in which case they are also known as "ground roll", or by other sources of seismic energy such as ocean waves an explosion or even a sledgehammer impact...
- Reflection seismologyReflection seismologyReflection seismology is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite/Tovex, a specialized air gun or a...
- Seismic refractionSeismic refractionSeismic refraction is a geophysical principle governed by Snell's Law. Used in the fields of engineering geology, geotechnical engineering and exploration geophysics, seismic refraction traverses are performed using a seismograph and/or geophone, in an array and an energy source...
- Seismic tomographySeismic tomographySeismic tomography is a methodology for estimating the Earth's properties. In the seismology community, seismic tomography is just a part of seismic imaging, and usually has a more specific purpose to estimate properties such as propagating velocities of compressional waves and shear waves . It...
- Structure of the EarthStructure of the EarthThe interior structure of the Earth, similar to the outer, is layered. These layers can be defined by either their chemical or their rheological properties. The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a...
- Reflection seismology
- Love
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Atmospheric sciences
- AeronomyAeronomyAeronomy is the science of the upper region of the atmosphere, where dissociation and ionization are important. The term aeronomy was introduced by Sydney Chapman, and the above definition stems from 1960. Today the term also includes the science of the corresponding regions of the atmospheres of...
– the study of the physical structure and chemistry of the atmosphere. - MeteorologyMeteorologyMeteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
– the study of weatherWeatherWeather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
processes and forecasting. - ClimatologyClimatologyClimatology is the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences...
– the study of weather conditions averaged over a period of time.
Geology
- MineralogyMineralogyMineralogy is the study of chemistry, crystal structure, and physical properties of minerals. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.-History:Early writing...
– the study of chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, crystal structureCrystal structureIn mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
, and physical (including opticalOptical mineralogyOptical mineralogy is the study of minerals and rocks by measuring their optical properties. Most commonly, rock and mineral samples are prepared as thin sections or grain mounts for study in the laboratory with a petrographic microscope...
) properties of mineralMineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s. - PetrophysicsPetrophysicsPetrophysics is the study of the physical and chemical properties that describe the occurrence and behavior of rocks, soils and fluids . Petrophysics mainly studies reservoirs of resources, including ore deposits and oil or natural gas reservoirs...
– The study of the origin, structure, and composition of rocks. - VolcanologyVolcanologyVolcanology is the study of volcanoes, lava, magma, and related geological, geophysical and geochemical phenomena. The term volcanology is derived from the Latin word vulcan. Vulcan was the ancient Roman god of fire....
– the study of volcanoVolcano2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
es, volcanic features (hot springHot springA hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...
s, geyserGeyserA geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...
s, fumaroleFumaroleA fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...
s), volcanic rock, and heat flow related to volcanoes.
Engineering
- Geological and geophysical engineering – the application of geophysics to the engineering design of facilities including roads, tunnels, and mines.
Water on the Earth
- GlaciologyGlaciologyGlaciology Glaciology Glaciology (from Middle French dialect (Franco-Provençal): glace, "ice"; or Latin: glacies, "frost, ice"; and Greek: λόγος, logos, "speech" lit...
– the study of ice and natural phenomena that involve ice, particularly glacierGlacierA glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s. - HydrologyHydrologyHydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
– the study of the movement, distribution, and quality of water on Earth and other planets. - Physical oceanographyPhysical oceanographyPhysical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.Physical oceanography is one of several sub-domains into which oceanography is divided...
– the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.
Organizations
- American Geophysical UnionAmerican Geophysical UnionThe American Geophysical Union is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 135 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international field of geophysics...
- Canadian Geophysical UnionCanadian Geophysical UnionThe Canadian Geophysical Union/Union géophysique canadienne began as a society dedicated to the scientific study of the solid earth and has evolved into one that is concerned with all aspects of the physical study of Earth and its space environment, including the Sun and solar system...
- Environmental and Engineering Geophysical SocietyEnvironmental and Engineering Geophysical SocietyThe Environmental and Engineering Geophysical Society is an international, applied scientific organization that has approximately 700 members. One of the society’s major activities is producing its annual meeting, the Application of Geophysics to Engineering and Environmental Problems...
- European Geosciences UnionEuropean Geosciences UnionThe European Geosciences Union is an interdisciplinary non-profit learned society open to individuals who are professionally engaged in or associated with geosciences, planetary and space sciences, and related studies.The mission statement of the EGU is "Dedicated to the pursuit of excellence in...
- International Union of Geodesy and GeophysicsInternational Union of Geodesy and GeophysicsThe International Union of Geodesy and Geophysics is a non-governmental organisation dedicated to the scientific study of the Earth using geophysical and geodesic techniques. The IUGG was established in 1919. Some areas within its scope are environmental preservation, reduction of the effects of...
- Royal Astronomical SocietyRoyal Astronomical SocietyThe Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
- Society of Exploration GeophysicistsSociety of Exploration GeophysicistsThe Society of Exploration Geophysicists is a nonprofit organization dedicated to promoting the science of geophysics and the education of exploration geophysicists. The Society fosters the expert and ethical practice of geophysics in the exploration and development of natural resources, in...
- Seismological Society of AmericaSeismological Society of AmericaThe Seismological Society of America is an international society devoted to the advancement of seismology and its applications in understanding and mitigating earthquake hazards and in imaging the structure of the Earth....
Publications
- Geophysics journals
- Important publications in geophysics (geology)
- Important publications in geophysics (physics)
Geophysics lists
See also
- Outline of geology
- Outline of physics