| Title | Secular variation in North America during historical times |
| Author | Newitt, L R; Dawson, E |
| Source | Geophysical Journal of the Royal Astronomical Society vol. 78, issue 1, 1984 p. 277-289, https://doi.org/10.1111/j.1365-246X.1984.tb06484.x |
| Year | 1984 |
| Alt Series | Earth Physics Branch, Contribution Series 1109 |
| Publisher | Wiley Online Library |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Canada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut |
| NTS | 1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65;
66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560 |
| Area | Canada; United States; Mexico |
| Lat/Long WENS | -168.0000 -50.0000 90.0000 14.0000 |
| Subjects | geophysics; geomagnetism; geomagnetic fields; geomagnetic variations; magnetic field; geological history; magnetic inclination; total field magnetics; magnetic declination; total magnetic
intensity |
| Illustrations | sketch maps; tables; time series; plots; histograms |
| |
| Abstract | The secular variation of the declination, inclination and total force of the geomagnetic field has been plotted for 74 locations in North America. A comparison of the occurrences of maxima and minima in
the SV curves from different stations shows little evidence of drift in North America. Although a declination maximum exhibits westward drift up to 1915, all other extrema in declination, inclination and total intensity occur almost simultaneously
over a wide area. The major feature of SV in North America appears to be a 4000 nT decrease in the total field since 1850, which may be due to a decrease in the dipole moment coupled with the decay of a large non-dipole anomaly situated under the
continent. Short-period changes in the rate of decrease are possibly jerks of the magnetic field. Maximum entropy spectral analysis of all three components of the field indicates periods of 102 and 53 yr. |
| GEOSCAN ID | 225701 |
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