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Geophysical survey

T
Tarek Mahmoud

Geophysical surveys use physical methods at the Earth's surface to measure subsurface physical properties and anomalies. Types of geophysical surveys include gravity, magnetic, electrical, seismic, radiometric, and geothermal methods. The gravity method measures minute variations in gravity caused by differences in subsurface density and distance from the Earth's center. Gravity surveys can be aerial or land-based, using a highly sensitive gravimeter. Processed gravity data is plotted on maps showing variations indicating subsurface densities, and is used for hydrocarbon exploration, mineral deposits, cavity detection, and other applications.

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Geophysical survey Gravity method
What is geophysical survey ? Exploration geophysics is an applied branch of geophysics, which uses physical methods, at the surface of the Earth to measure the physical properties of the subsurface, along with the anomalies in those properties.
Types of geophysical survey 1. Gravity methods 2. Magnetic methods 3. Electrical methods 4. Seismic methods 5. Radiometric methods & 6. Geothermal method
Gravity is the force by which a planet or other body draws objects toward its center What is gravity?
If the earth was a perfect sphere and was composed of the same material throughout, gravity would be the same anywhere on the surface. However because the planet is slightly squashed, gravity at the poles is slightly higher than at the equator due to the slightly shorter distance to the centre of the earth to the poles.
The strength of gravitational field is directly proportional to the density of subsurface substances
Gravity method (or) gravity survey Gravity surveys measure minute variations in gravity. Gravity at every point on the surface of the earth varies slightly depending on: distance from the equator density of the underlying rocks
Gravity surveys can be can be either aerial or land-based. How Is A Gravity Survey Done?
gravitymeter Gravitymeter measures the variation in earths gravitational fieldThe gravity meter or gravimeter is a very delicate instrument as. It is highly sensitive and great care is required Once the gravity measurements have been collected data are processed by the geophysicist.The data is then plotted as a computer-generated map
Results obtained from gravitymeter It shows variations in gravity due to the presence of subsurface substances of varying densities
Applications of gravity surveying Hydrocarbon exploration Estimation of, mineral deposits Detection of sub-surface cavities (micro-gravity) Location of buried rock valleys Determination of glacier thickness Shape of earth (geodesy)

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Geophysical survey

  • 2. What is geophysical survey ? Exploration geophysics is an applied branch of geophysics, which uses physical methods, at the surface of the Earth to measure the physical properties of the subsurface, along with the anomalies in those properties.
  • 3. Types of geophysical survey 1. Gravity methods 2. Magnetic methods 3. Electrical methods 4. Seismic methods 5. Radiometric methods & 6. Geothermal method
  • 4. Gravity is the force by which a planet or other body draws objects toward its center What is gravity?
  • 5. If the earth was a perfect sphere and was composed of the same material throughout, gravity would be the same anywhere on the surface. However because the planet is slightly squashed, gravity at the poles is slightly higher than at the equator due to the slightly shorter distance to the centre of the earth to the poles.
  • 6. The strength of gravitational field is directly proportional to the density of subsurface substances
  • 7. Gravity method (or) gravity survey Gravity surveys measure minute variations in gravity. Gravity at every point on the surface of the earth varies slightly depending on: distance from the equator density of the underlying rocks
  • 8. Gravity surveys can be can be either aerial or land-based. How Is A Gravity Survey Done?
  • 9. gravitymeter Gravitymeter measures the variation in earths gravitational fieldThe gravity meter or gravimeter is a very delicate instrument as. It is highly sensitive and great care is required Once the gravity measurements have been collected data are processed by the geophysicist.The data is then plotted as a computer-generated map
  • 10. Results obtained from gravitymeter It shows variations in gravity due to the presence of subsurface substances of varying densities
  • 11. Applications of gravity surveying Hydrocarbon exploration Estimation of, mineral deposits Detection of sub-surface cavities (micro-gravity) Location of buried rock valleys Determination of glacier thickness Shape of earth (geodesy)