Magnetic Maps

Magnetic Maps


maps of the earth’s surface on which iso-lines (isodynamic, isogonic, and isoclinal) are used to show the distribution of the intensity of the geomagnetic field or its components.

Magnetic maps of the world and of anomalous magnetic fields are most common. World maps reflect the basic characteristics of the main geomagnetic field (the normal field), the source of which is considered to be the movement of electroconductive matter in the earth’s core. The dimensions of the structural features of the main field approximate the dimensions for the continents, so that the usual scale of the world maps is 1:10,000,000 or less. Deviations caused by irregularities in the structure of the earth’s crust, the occurrence of ore deposits, and other local factors are smoothed out on the world maps, but maps of anomalous magnetic fields reflect local deviations of the geomagnetic field from the main. These deviations are ordinarily observed in areas whose linear dimensions are on the order of dozens of km or less. Therefore, magnetic maps of anomalous fields are on a larger scale than world maps (for example, 1:200,000) and are usually compiled on the basis of aeromagnetic surveying. Magnetic maps are essential in studying the structure of the earth’s interior and in prospecting for minerals. Owing to secular changes in the earth’s magnetic field, magnetic maps go out of date and must be redone periodically (every five or ten years).


lanovskii, B. M. Zemnoi magnetizm [3rd ed.], vol 1. Leningrad, 1964.


References in periodicals archive ?
Visitors can then create their own weather forecasts on magnetic maps on the "weather wall".
A visual study of magnetic maps can be fruitful for preliminary interpretation (Telford et al, 1998) Visual studies of total aeromagnetic intensity contour map (Figure 2) and the residual aeromagnetic intensity contour map (Figure 3) of Wamba and its adjoining areas revealed variations in magnetic field intensity throughout the area.
Another instrument on SDO, the Helioseismic and Magnetic Imager (HMI), provides magnetic maps of the sun.
The Solar Optical Telescope images and magnetic maps uncover highly dynamic, intermittent nature of the sun's lower atmosphere -- chromosphere.
Dessler of the University of Arizona in Tucson says the study indicates that magnetic maps of Jupiter generated form Voyager data are more accurate than those form Pioneer 141.
A comparison with magnetic maps of the photosphere, obtained with the Helioseismic Magnetic Imager aboard SDO, showed that the cells were centered on unipolar flux concentrations, but left doubt about whether the cellular emission was coming from the tops of closed loops near the Sun's surface, or from longer field lines that extend higher into the corona.
The magnetic maps were from the Michelson Doppler Imager (MDI) instrument on board Solar and Heliospheric Observatory (SOHO) spacecraft.
These properties were staked based on the processing of data contained within Quebec'sMinistere de l'Energie et des Ressources 1988 "32G/05 - Lac Margry (DV88-08)" total field and vertical gradient magnetic maps.
The grid areas covered major boundary zones on regional airborne magnetic maps, and on the location of known mineral occurrences, geochemical anomalies and previously defined conductors.
Preliminary geological sketches of the interpretive model, regional total field magnetic maps and photographs of the polished drill core section reported above have been added to the Company's website at www.
See enhanced total field magnetic map at this location: http://www2.
Perdeck 1958), juvenile migrants on their first migration would not be expected to use a magnetic map.