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PROCEDES DE FILTRAGE ET DE FOCALISATION DE CHAMP POUR LA DETECTION ELECTROMAGNETIQUE DES CARRIERES SOUTERRAINES *
Author(s) -
DUBUS J. P.,
CLICQUE D.,
BAUDET J.,
GABILLARD R.
Publication year - 1978
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1978.tb01602.x
Subject(s) - geology , transmitter , mineralogy , hydrogeology , interpretation (philosophy) , conductivity , physics , geotechnical engineering , computer science , telecommunications , channel (broadcasting) , quantum mechanics , programming language
A bstract The electromagnetic surface detection of underground quarries by classical methods becomes difficult when they are situated at depths greater than ten meters and when the thickness and conductivity of the superficial layers are irregular. The problem is tackled in two stages: at first using successive approximations, characteristics of the miscellaneous layers of a stratified medium are identified, and the quarries are then detected by observation of the conductivity changes of one of the lower layers. Computer interpretation, however, is necessary. The chances of detection of the quarries are considerably improved by a field localization method developed by us: computer interpretation is eliminated. The new aspect is an auxiliary transmitter which annuls the currents induced by the principal transmitter in the uppermost—generally more conductive—layers. The theoretical and experimental results show that the probability of detection of the quarries by this method are four times as high as by the classical one.