Open AccessA Geomagnetic Variation Anomaly in the Northern Pyrenees * †
Author(s) -
Babour K.,
Mosnier J.,
Daignieres M.,
Vasseur G.,
Mouel J. L.,
Rossignol J. C.
Publication year - 1958
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1958.tb05345.x
Subject(s) - geology , geophysics , basement , anomaly (physics) , magnetic anomaly , geodesy , polar , seismology , physics , civil engineering , astronomy , engineering , condensed matter physics
Summary Sixty stations measuring the time variations of the Earth's magnetic field were operated from 1972 to 1974 in the Northern Pyrenees. Magnetograms show a very large anomaly in the vertical and horizontal variation fields for the period range from a few minutes to a few hours. Owing to the particular measurement and reduction techniques used it was possible to show that, for the above period range, the anomalous field is the product of a function of space by a function of time. This anomaly corresponds to a current concentration the geometry of which is invariant with time. Most of the currents associated with the anomaly flow at a depth smaller than 15km. The orientation of the conductive structure is different from the orientation of superficial structures; this structure could correspond to old sedimentary basins inside the palaeozoic basement or (and) to a hidden accident in the basement as suggested by seismic evidence.