The deviation of the total geomagnetic field direction from the dipole field direction as a manifestation of the non-dipole field

1980 ◽  
Vol 24 (2) ◽  
pp. 153-162
Author(s):  
Alena Janáčková ◽  
Jan Anděl ◽  
V. Kropáček
Keyword(s):  
Geomagnetic Field ◽  
Field Direction ◽  
Dipole Field

Geophysical Studies of North African Cenozoic Volcanic Areas: III. Garian, Libya

1975 ◽  
Vol 12 (8) ◽  
pp. 1264-1271 ◽  
Author(s):  
J. M. Ade-Hall ◽  
Susann Gerstein ◽  
Robert E. Gerstein ◽  
Peter H. Reynolds ◽  
P. Dagley ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Field Direction ◽  
Dipole Field ◽  
Plate Motion ◽  
Paleomagnetic Data ◽  
North African ◽  
Axial Dipole ◽  
Repeated Sampling ◽  
Absolute Age ◽  
E 32

Paleomagnetic and K/Ar whole rock absolute age data are described for material from the Garian area of Libya, centered at 13°E, 32°N. Within-unit cleaned paleomagnetic directions from the essentially unaltered lavas are very well defined and can almost certainly be taken as reliable measurements of the geomagnetic field direction during the initial cooling of each flow. However, the distributions of mean direction, from which the effect of repeated sampling of the field at one time has been removed, does not suggest that a reversing axial dipole field has been recorded in a representative manner. Both N and R groups of directions are azimuthally elongated, and the average poles for the N and R groups differ by 21°, or four times the 95% level uncertainty for each average pole. A number of possible physical explanations for the paleomagnetic results are discussed. The conventional overall average pole at 88°N, 123°E, δp: 3°, δm: 7 °does not differ significantly from the geographic pole, a result which agrees closely with that of Schult and Soffel (1973). However, the value of these overall average poles in estimating absolute plate motion must await an understanding of the sources of the asymmetries in the paleomagnetic data.

Ionospheric super-bubble effects on the GPS positioning relative to the orientation of signal path and geomagnetic field direction

GPS Solutions ◽  
2011 ◽  
Vol 16 (2) ◽  
pp. 181-189 ◽  
Author(s):  
V. V. Demyanov ◽  
Yu. V. Yasyukevich ◽  
A. B. Ishin ◽  
E. I. Astafyeva
Keyword(s):  
Geomagnetic Field ◽  
Field Direction ◽  
Gps Positioning ◽  
Signal Path

scholarly journals Preliminary palaeomagnetic investigation of riverine tufa: is riverine tufa a reliable recorder of the geomagnetic field direction?

2010 ◽  
Vol 183 (3) ◽  
pp. 1231-1238 ◽  
Author(s):  
Hayao Morinaga ◽  
Mizuki Toda ◽  
Hirooki Fujino ◽  
Natsuki Hasegawa
Keyword(s):  
Geomagnetic Field ◽  
Field Direction

scholarly journals Possible consequences of a dwindling geomagnetic field

1971 ◽  
Vol 2 (3) ◽  
pp. 46
Author(s):  
I.K. Crain
Keyword(s):  
Geomagnetic Field ◽  
Dipole Field

Recently, Facer (1971) has discussed the problem of the dwindling of the geomagnetic field, and estimated that in 810 years (AD 2781) the dipole and non-dipole fields will be roughly equal and that in 1931 years (AD 3902) the dipole field will be essentially zero. Various authors (Crain and Crain, 1970; Cox, 1968; Parker, 1969) have suggested that these conditions are highly favourable for the production of geomagnetic reversals.

Paleomagnetic Evidence for Repeated Glacial Lake Missoula Floods from Sediments of the Sanpoil River Valley, Northeastern Washington

1991 ◽  
Vol 35 (2) ◽  
pp. 197-207 ◽  
Author(s):  
William K. Steele
Keyword(s):  
Secular Variation ◽  
Geomagnetic Field ◽  
Remanent Magnetization ◽  
River Valley ◽  
Field Direction ◽  
Glacial Lake ◽  
Laboratory Measurements ◽  
Eastern Washington

AbstractRecent explanations of widespread rhythmically layered sediments in eastern Washington as the result of repeated great floods from glacial Lake Missoula implicitly suggest a paleomagnetic test for validity. If each conjectural flood layer is separated by years or decades, as hypothesized, a sequence of several such flood beds should record measurable secular variation in geomagnetic field direction. In the Sanpoil River valley where the rhythmite sequences are thought to have been deposited in glacial Lake Columbia, the paleomagnetic test consists of measuring remanent magnetization (RM) directions for thick, upwardly fining beds inferred to be sediments deposited by the influx of flood waters from glacial Lake Missoula into glacial Lake Columbia. Laboratory measurements of samples from three widely spaced sections along the Sanpoil River yield RM vectors with erratic inclinations, apparently affected by varying contributions of inclination error and (or) compaction shallowing, but with declinations that generally differ statistically from one flood to the next and that show the same west-to-east trend at all three locations. The rates of declination change inferred from these data are consistent with modern rates, thus providing the first geophysical evidence supporting the timing in the tens-of-floods theory.

scholarly journals Features of the next reversal of the geomagnetic field

2021 ◽  
pp. 131-140
Author(s):  
В.В. Кузнецов
Keyword(s):  
Geomagnetic Field ◽  
Dipole Field ◽  
Total Field

В статье обсуждаются возможность проявления очередной инверсии геомагнитного поля (ГМП) и его некоторые особенности. Дипольное поле (ДП) приблизится к нулевой отметке, которую достигнет примерно в 3500 году. С 1500 года, на фоне понижения ДП происходит рост октупольного и квадрупольного компонент ГМП и их суммы (О+К). ДП, согласно нашей модели геомагнетизма, после прохождения нулевой отметки начнет расти с обратным знаком и противодействовать (О+К) полю, понижая его уровень до нуля. В этот момент (≈ 6000 год) поле (N) будет иметь минимальную величину. Затем начнется рост ДП обратного значения (R). Инверсия закончится при достижении этим полем устойчивой величины. The possibility of a new reversal of the geomagnetic field (GMF) and some of its features are discussed. In 3500 the dipole field (DF) will become near zero. Since 1500, along with the decrease of DF, there has been an increase of the octupole and quadrupole components of the GMF as well as their sum (O+Q). According to our model of geomagnetism, after passing the zero the reversing DF will start its rise counteracting the (O+Q) field and lowering its value to zero. In about 6000 the total field DF+O+Q (N) will be minimum. After DF reaches a stable value the reversal will complete.

New technique to diagnose the geomagnetic field based on the single circular current loop model

2020 ◽  
Author(s):  
Zhaojin Rong ◽  
Yong Wei ◽  
Wenyao Xu ◽  
Dali Kong ◽  
Jun Cui ◽  
...  
Keyword(s):  
Electric Current ◽  
Geomagnetic Field ◽  
Dipole Field ◽  
New Technique ◽  
Current Loop ◽  
Loop Model ◽  
Effective Technique ◽  
Circular Current ◽  
Planetary Magnetism ◽  
Geomagnetic Dipole

<p>A quick and effective technique is developed to diagnose the geomagnetic dipole field based on an unstrained single circular current loop model. In comparsion with previous studies, this technique is able to separate and solve the loop parameters successively. With this technique, one can search the optimum full loop parameters quickly, including the location of loop center, the loop orientation, the loop radius, and the electric current carried by the loop, which can roughly indicate the locations, sizes, orientations of the interior current sources. The technique tests and applications demonstrate that this technique is effective and applicable. This technique could be applied widely in the fields of geomagnetism, planetary magnetism and palaeomagnetism. The further applications and constrains are discussed and cautioned.</p>

Estimating the Magnetization Direction of Sources through Correlation between Reduced-to-Pole Anomaly and Normalized Source Strength

2014 ◽  
Vol 644-650 ◽  
pp. 3793-3796
Author(s):  
Liang Hui Guo ◽  
Rui Gao ◽  
Guo Li Zhang
Keyword(s):  
Geomagnetic Field ◽  
Remanent Magnetization ◽  
Cross Correlation ◽  
Synthetic Data ◽  
Field Direction ◽  
Magnetic Data ◽  
Source Strength ◽  
Magnetization Direction ◽  
New Approach ◽  
Total Magnetization

Under the effects of remanent magnetization, total magnetization direction is different from geomagnetic field direction, which makes magnetic data processing and interpretation complexity. In this paper, we present a new approach for estimating the total magnetization direction of sources via cross-correlation between the reduced-to-pole anomaly and the normalized source strength (who is less sensitive to remanent magnetization). The geomagnetic field direction is used to calculated the normalized source strength, while various assumed total magnetization directions are used to calculated the RTP anomalies. The maximum correlation between the RTP anomalies and the normalized corresponds to the estimated total magnetization direction. Test on synthetic data showed that the new approach is simple and effective.

Geomagnetic field direction in Paris since the mid-sixteenth century

1996 ◽  
Vol 98 (3-4) ◽  
pp. 321-360 ◽  
Author(s):  
Mioara Alexandrescu ◽  
Vincent Courtillot ◽  
Jean-Louis Le Mouël
Keyword(s):  
Sixteenth Century ◽  
Geomagnetic Field ◽  
Field Direction
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