Open AccessA study of diurnal variation of the electromagnetic field in northern France using ancient recordings
Author(s) -
Counil J. L.,
Mouël J. L.,
Menvielle M.
Publication year - 1984
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.1984.tb05073.x
Subject(s) - observatory , variation (astronomy) , geology , geodesy , schumann resonances , seismology , geophysics , physics , astronomy , ionosphere
Summary. From 1883 to 1901 magnetic elements were continuously recorded at the French Saint‐Maur observatory. From 1893 to 1895, Earth potentials along two 15 km long orthogonal lines were also recorded. Moreover, from 1884 to 1885, Blavier,‘Ingénieur des Télégraphes’, used several some hundred kilométre long telegraphic lines to measure and record Earth potentials. Using this set of data we will study the daily variations of the telluric and magnetic fields and the way according to which these two fields are correlated. The observed magnetotelluric tensor is antisymmétric when the long telluric lines are considered. It is not the case for the short lines. But, making use of a correction derived from the formalism developed by Le Mouel & Menvielle in the static distortion approximation, one can derive an impedance whose phase is equal to the phase of the impedance derived from the long line data.