Open AccessInterpretation of VLF-EM anomalies of 3D structures by using linear filtering techniques
Author(s) -
M. Djeddi,
H. A. Baker,
Alain Tabbagh
Publication year - 1998
Publication title -
annals of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 60
eISSN - 2037-416X
pISSN - 1593-5213
DOI - 10.4401/ag-4329
Subject(s) - anomaly (physics) , interpretation (philosophy) , position (finance) , filter (signal processing) , geology , algorithm , geophysics , computer science , physics , finance , economics , computer vision , programming language , condensed matter physics
For almost four decades now, the VLF-EM method has been used to locate different conducting structures. The interpretation is usually carried out on a profile anomaly where a possible estimation of the depth and the dip can be obtained. The maps are only used, after applying the Fraser filter, to best position the anomaly and no further quantitative interpretation is given. In this paper a linear filtering technique is developed based on the X and Y derivatives of the VLF-EM anomaly. This technique helps in determining the exact dimensions of the causative structures as well as their depths regardless of their conductivities. This work also shows that the known Fraser filter that is usually applied on a profile data can be adapted, for the first time, in studying quantitatively 3D structures if it is applied to raw data in the X and Y directions. It can now be used to estimate the dimensions of the targets