Magnetic Survey

magnetic survey

[mag′ned·ik ′sər‚vā]
(geophysics)
Magnetometer map of variations in the earth's total magnetic field; used in petroleum exploration to determine basement-rock depths and geologic anomalies.
Measurement of a component of the geomagnetic field at different locations.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Magnetic Survey

 

systematic measurements of the components of geomagnetism and compilation of magnetic charts based on measurement data.

A distinction is made between general and detailed magnetic surveys. A general magnetic survey, which is carried out over large areas with a comparatively sparse network of measurement sites (separated by tens or hundreds of kilometers), provides for the study of the basic principles governing the distribution of the geomagnetic field. Charts compiled on the basis of a general magnetic survey are essential for maritime and air navigation, for finding significant magnetic anomalies, and for studying the secular change of the components of geomagnetism. A detailed magnetic survey with a distance of 1 m to several kilometers between measurement sites (strips) is used mainly for geological mapping and prospecting for ore deposits.

In a magnetic survey the absolute value of the vector of the total intensity of the geomagnetic field is usually measured, but for purposes of geological surveys efforts are often limited to relative determination of the vertical component of the field. A magnetic survey is carried out by various types of magnetometers carried by satellites, aircraft, nonmagnetic ships, and surface vehicles. Continuous observations of variations in the geomagnetic field over time (the secular change of the field) are made by networks of magnetic observatories.

REFERENCE

lanovskii, B. M. Zemnoi magnetizm [3rd ed.], vol. 1. Leningrad, 1964.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The magnetic survey as designed encompasses the Primary Ridge porphyry target, the 'Red Springs' porphyry target and the east section of the Razorback porphyry target involving approx.
The magnetic survey as designed encompasses the Primary Ridge porphyry target, the "Red Springs" porphyry target and the east section of the Razorback porphyry target involving approx.
Begin a sub-audio magnetic survey (SAM) of possible extensional targets at Carlow Castle West;
Osino has drilled 4,660 metres on the Twin Hills West targets as well as a sampling and ground magnetic survey program, which defined the new gold anomaly.
The magnetic survey delineated three anomalous zones; two high magnetic zones (zone 1 ### 2) in the south-eastern side and one narrow zone of low magnetism (zone 3) in the NW-SW direction.
A magnetic survey was carried out in 1977 at the southeast of the discovered decorative structures (Figure 2(a)) [11].
These surveys included a magnetic survey, which is the measurement of the magnetic field in the area - this allows us to understand the geological structure of the site," he added.
It has completed the scope of work including semi-detailed magnetic survey on 28 topo sheets covering 18000 sq.km area, the sources said and added total magnetic survey data was recorded using Proton Precession Magnetometer, Geometric G856AX, and after applying necessary corrections prepared 2D contour maps using surfur-11.
The company has finished an airborne magnetic survey and will shortly be embarking on an HTEM (helicopter-borne time-domain electromagnetic) survey of its claims.
In conjunction with the agreement, the company has secured an onshore airborne gravity and magnetic survey in the Southern Mozambique Basin.