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VLF GROUND SURVEYS, A POWERFUL TOOL FOR THE STUDY OF SHALLOW TWO‐DIMENSIONAL STRUCTURES *
Author(s) -
FISCHER G.,
QUANG B. V.,
MÜLLER I.
Publication year - 1983
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.1365-2478.1983.tb01100.x
Subject(s) - geology , dike , anisotropy , geophysics , igneous petrology , seismology , regional geology , electrical resistivity and conductivity , economic geology , polar , gemology , environmental geology , engineering geology , geodesy , telmatology , tectonics , petrology , volcanism , physics , quantum mechanics , astronomy
A bstract The suitability of VLF ground surveys in the investigation of shallow two‐dimensional structures is analyzed. For such structures the polar formalism is derived, necessary in practice since the transmitters are generally not in the structural strike or profile. A simple vertical dike is considered to demonstrate the striking anisotropy which can be expected over such a structure, in particular the high apparent resistivity along the direction of a well‐conducting dike and the low resistivity across it. The theory is then confronted with the practical example of an asymmetrical vertical dike resulting from a strike‐slip fault. Modelling of the survey results is very successful and yields good confirmation of the polar behaviour. VLF ground surveys thus provide a quick and powerful tool for the study of geological accidents within about 100 m of the surface.