Gravity Gradiometry

Gravity Gradiometry

Gravity gradiometry is the study and measurement of variations in the acceleration due to gravity.

Gravity gradiometry is a measure of differential acceleration of the earth’s gravity field over a unit distance. It is used by oil, gas and mining companies to directly measure the density of the subsurface, effectively the rate of change of rock properties. From this information they can build up a picture of subsurface anomalies and more accurately target oil, gas and mineral deposits.

Gravity gradiometry measure gradients of the gravity acceleration that can be used indirectly to estimate the vertical gradient of the gravity acceleration (Gdd) and a proxy for gravity (very close to it gD).

These systems have been ported to helicopters to allows a longer time of acquisition and reduce the noise/signal ratio.

Gdd is measured in a similar way to magnetics survey and the bandwidth goes down to 500m and less. Consequently, Gdd lacks long wavelength. It is generally accepted that Gdd does not contain wavelength greater than 1/2 the size of the survey, and this has consequences on the depth of investigation. Gdd data is not always useful in crustal scale studies but very powerful for mineral exploration.

A gradiometer consists of two gravimeters, which experience the same aircraft accelerations, and Earth tides, and latitude effects etc. The gradient is simply the subtraction of one gravimeter response from the other.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Gravity field and steady-state ocean circulation explorer — GOCE Typ: Forschungssatellit Land: Europa Behörde: ESA NSSDC ID: 2009 013A Missionsdaten Masse …   Deutsch Wikipedia

  • Near-surface geophysics — is the use of geophysical methods to investigate small scale features in the shallow (tens of meters) subsurface. It is closely related to applied geophysics or exploration geophysics. Methods used include seismic refraction and reflection,… …   Wikipedia

  • Exploration 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 concentrations of ore minerals and hydrocarbons. Exploration… …   Wikipedia

  • Measuring instrument — Captain Nemo and Professor Aronnax contemplating measuring instruments in Twenty Thousand Leagues Under the Sea …   Wikipedia

  • SGG — abbr. Satellite Gravity Gradiometry …   Dictionary of abbreviations

  • GOCE — Typ: Forschungssatellit Land (Organisation): Europa (ESA) Missionsdaten Masse: 1100 kg Größe …   Deutsch Wikipedia

  • Geophysical MASINT — is a branch of Measurement and Signature Intelligence (MASINT) that involves phenomena transmitted through the earth (ground, water, atmosphere) and manmade structures including emitted or reflected sounds, pressure waves, vibrations, and… …   Wikipedia

  • Satellite geodesy — is the measurement of the form and dimensions of the Earth, the location of objects on its surface and the figure of the Earth s gravity field by means of satellite techniques. In other words, geodesy by means of satellites. It belongs to the… …   Wikipedia

  • Space techniques — In geodesy, the term Space techniques includes modern measuring methods which make use of artificial satellites, interplanetary space probes and of quasars.Space techniques are nowadays an important supplement of classical geodetic methods like… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”