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STATISTICAL ANALYSIS OF AIRBORNE ELECTROMAGNETIC SIGNATURES OF DIFFERENT CONDUCTOR GROUPS IN TROPICAL TERRAIN OF KARNATAKA, INDIA *
Author(s) -
CHOUDHURY KALPAN
Publication year - 1982
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.1365-2478.1982.tb01300.x
Subject(s) - amplitude , logarithm , exponential decay , electrical conductor , geology , exponential function , conductor , channel (broadcasting) , mineralogy , physics , mathematics , mathematical analysis , geometry , optics , electrical engineering , engineering , quantum mechanics , nuclear physics
A bstract AEM (airborne electromagnetic) anomalies caused by massive sulphide conductors and superficial conductors can be recognized with a statistical method, as shown by an analysis of Input AEM data from Karnataka State. The weathering in the survey area is of tropical type. Parameters, such as various amplitude ratios and time parameters (inverse of decay rate) for exponential and power‐law decay were analyzed for sulphide bodies, conducting soil, superficial conductors, and cultural conductors. Time parameters τ 1 (exponential decay) is defined as ratio of time differences between the third and fourth channel to the logarithmic value of the relative amplitude of the two channels. Time parameter K 1 (power‐law decay) is defined as ratio of the difference of the logarithmic values of the delay times of the third and fourth channels to the logarithmic value of the relative amplitude of the two channels. The two parameters have been useful in recognizing sulphide conductors. Also the first channel Input amplitude and logarithmic plot of the transients appear to be helpful in conductor identification. Channel ratios seem to be the least effective parameters of conductor identification. In the area studied both power‐law and the conventional exponential decay were found equally suitable for approximating Input AEM transients.