Accession Number : AD0428953

Title :   COHERENCY OF GEOELECTROMAGNETIC SIGNALS.

Corporate Author : CALIFORNIA UNIV BERKELEY SPACE SCIENCES LAB

Personal Author(s) : Ward,S. H. ; Fournier,H. G.

Report Date : 06 NOV 1963

Pagination or Media Count : 16

Abstract : By theory and observation it is possible to demonstrate that the coherency between orthogonal electric and magnetic time series used in magnetotelluric sounding is a function of (1) the direction of the measuring axes, (2) the anisotropy ratio, (3) the coherency between the orthogonal H components, (4) the relative magnitudes of the orthogonal H components, and (5) the frequency. Similarly, the coherency between orthogonal electric time series measured in a telluric survey is a function of many variables including all five items listed. Experimental data is presented which illustrates the dependence of coherency on the direction of the resultant telluric vector. The mentioned coherencies can change over relatively short periods of time and when they reach low values, the reliability of either of the magnetotelluric or telluric methods is apt to be reduced. (Author)

Descriptors :   (*GEOMAGNETISM, GEOPHYSICS), MAGNETIC FIELDS, ELECTRIC FIELDS, ANISOTROPY

Distribution Statement : APPROVED FOR PUBLIC RELEASE