gravimeter


Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.
Related to gravimeter: gravimetric analysis

gravimeter

1. an instrument for measuring the earth's gravitational field at points on its surface
2. an instrument for measuring relative density

Gravimeter

 

an instrument for the relative measurement of the acceleration due to gravity. Most gravimeters consist of accurate spring or torsion balances.

Differences in the acceleration due to gravity are measured by means of such gravimeters according to the change in the deformation of a spring or the angle of twist of an elastic thread that are compensating the force of gravity on a small weight. Measurements are made first at a starting point, for which the acceleration due to gravity is known, and then at the point being studied. The main difficulty in constructing a gravimeter is the need to provide precise measurement of small elastic deformations under field conditions. Optical, photoelectric, capacity, and inductive means of recording are used. Gravimeters are used that are based on measurement of the change in frequency of vibration of a string from which a weight is suspended or of the change in rate of precession of gyroscopic instruments because of different forces of gravity at the different points of measurement. The best gravimeters are sensitive to within a few ten-thousandths of a milligal.

There are special gravimeters for measuring the force of gravity at the bottom of shallow bodies of water, in surface and submarine vessels, and in airplanes. For measurements from moving objects, gravimeters are equipped with auxiliary apparatus that records the inclination of the base of the instrument and the acceleration caused by rolling. Some gravimeters make possible the continuous recording of solar-lunar variations in gravity over a period of several months. To calibrate gravimeter readings, measurements are made at points for which the difference in the acceleration due to gravity is known or at a single point with different inclinations of the gravimeter.

Surface and borehole gravimeters provide measurements of the acceleration of gravity that are accurate to 0.01 milligal; sea-bottom gravimeters, to 0.05 milligal; marine shipmounted gravimeters, to 0.5 milligal; and airborne gravimeters, to 5 milligals.

REFERENCES

Lukavchenko, P. I. Gravimetricheskaia razvedka na neft’ i gaz. Moscow, 1956.
Veselov, K. E., and M. U. Sagitov. Gravimetricheskaia razvedka. Moscow, 1968.
Spravochnik geofizika, vol. 5. Moscow, 1968.

P. I. LUKAVCHENKO and M. U. SAGITOV

gravimeter

[grə′vim·əd·ər]
(engineering)
A highly sensitive weighing device used for relative measurement of the force of gravity by detecting small weight differences of a constant mass at different points on the earth. Also known as gravity meter.
References in periodicals archive ?
The Estonian Land Board (ELB) and the National Geospatial-Intelligence Agency (NGA) of the USA are thanked for the Scintrex and LCR gravimeter respectively, Geosoft Ltd.
Three points of the I order network were observed with a JILAg-5 absolute gravimeter by the FGI.
And, no isolating system, no matter how "super," is perfect for isolating the needed macroscopic parts of the system, whether they be for an atom or for a corner-cube-based absolute gravimeter.
Nawa and his colleagues went on to analyze more gravimeter data from the South Pole, as wall as from stations in Brazil, Alaska, Canada, Hawaii, Peru, California, Australia, and Tonga.
Somedoubt that the magnitude of such inertial waves would be great enough to be picked up by the gravimeter.
The Seventh International Comparison of Absolute Gravimeters ICAG-2005 at the Bipm, Harita Dergisi 18: 382-387.
Micro-g Solutions is a Colorado-based geophysical instrument company and the world's only commercial manufacturer of absolute gravimeters for the geophysical research community and the oil and gas industry.
Gravity readings are stored into the internal memory of the gravimeter.
Contract notice: Supply of OP RDI - Portable Digital gravimeter,
A gravimeter aboard the DC-8 will detect subtle differences in gravity to map the ocean floor beneath floating ice shelves.
Announcement of competition: Purchase of portable relatively gravimeter
Radar instruments from the University of Kansas and a gravimeter from Columbia University will allow scientists to "see" snow, ice, and bedrock characteristics at depths below the surface.