- Branche: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- Company Profile:
Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
A gravimeter consisting of a wire which is kept vibrating in an electrostatic or magnetic field by passing a current of fixed, precise frequency through it. The rate of vibration is proportional to the force of gravity and is determined by the weight of the wire and by the frequency of the current. A change in gravity can be detected by the change in electrical frequency necessary to keep the wire vibrating at its initial, fixed frequency. An accuracy of better than 1 mgal can be obtained in a few minutes. There are many varieties of instrument built on this principle. Vibrating string instruments have been used, for example, for measuring the density of the medium surrounding the wire.
Industry:Earth science
(1) The integral ∫<sup>H'</sup><sub>o</sub> (g/g<sub>o</sub>)dH <br>
Industry:Earth science
(1) The science concerned with the forces which act in and on the Earth and with the changes caused by these forces. (2) The study of the Earth by quantitative physical methods. (3) The physics of the Earth and its environment. Geophysics is a subdivision of geology and commonly is divided into two disciplines: geostatics, which concerns the Earth as a body in equilibrium; and geodynamics, which concerns the Earth as a body changing in response to applied forces. Although special terms have been invented to denote the application of geophysical methods to the Moon and other planetary bodies, the present tendency is to apply geophysics to all such studies.
Industry:Earth science
(1) That part of geodesy which deals with problems on a rotational ellipsoid used as a reference surface. (2) The study of the geometry of the terrestrial ellipsoid and representation of important parts of its surface on the sphere and plane.
Industry:Earth science
A block of rock or sediment dropped between two approximately parallel faults, with the length of the block being much greater than the width and parallel to the bounding faults.
Industry:Earth science
A gravimeter designed to measure the difference between the value of gravity at one station and that at another, or the ratio between the values of gravity at the two stations.
Industry:Earth science
A torsion balance designed to be particularly sensitive to vertical differences of gravity.
Industry:Earth science
A static gravimeter containing a spring wound in such a manner that elongation of the spring under the weight of the attached mass is equal to the distance between the points of attachment of the spring. The spring has, effectively, a length of zero when it is not elongated.
Industry:Earth science
A device for listening to faint sounds transmitted through the earth. The sounds are those produced by explosion or by mechanical devices.
Industry:Earth science
Any faint image, on a negative or plate, which barely prints or fails to print.
Industry:Earth science
