Accession Number:

AD0256422

Title:

AN ANALYSIS OF THE MAGNETOTELLURIC METHOD FOR DETERMINING SUBSURFACE RESISTIVITIES

Descriptive Note:

Corporate Author:

TEXAS UNIV AUSTIN ELECTRICAL ENGINEERING RESEARCH LAB

Personal Author(s):

Report Date:

1961-02-28

Pagination or Media Count:

1.0

Abstract:

Theoretical and experimental features of the magnetotelluric method of determining the electrical resistivities of the earths subsurface structures were investigated. Mathematical models consisting of multiple homogeneous and isotropic resistive layers in a semi-infinite half space were analyzed, and a set of normalized apparent resistivity curves were derived for a twolayer model. A theoretical treatment of the data analysis procedures is presented with particular emphasis on the power spectrum and cross spectrum analysis performed by the direct filtering method. It is pointed out that it is unnecessary and often undesirable to treat the data recordings as stationary time series. Many of the fluctuations in the resistivity estimates are the result of the presence of two-dimensional inhomogeneities and anisotropies and may not be averaged out in the usual statistical sense. Recordings made of the fluctuations of the magnetotelluric fields were analyzed and the results of these analyses are presented. A brif description of the data recording and analysis equipment is also included. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE