The magnetotelluric phase tensor

The relationship between the magnetotelluric tensor invariants and the phase tensor of Caldwell, Bibby and Brown

In recent papers Caldwell, Bibby and Brown (2002, 2003) (hereafter referred to as CBB) have introduced a new and elegant method for analysing magnetotelluric (MT) data which can be applied directly to galvanically distorted data in a regional conductivity structure of any dimension. It is therefore more general and direct than previous methods (e.g. Bahr, 1988; Groom and Bailey, 1989; Smith, 19...

WALDIM: A code for the dimensionality analysis of magnetotelluric data using the rotational invariants of the magnetotelluric tensor

In the magnetotelluric (MT) method, the analysis of geoelectric dimensionality has acquired special importance in the last years, because numerical codes have made it possible to model and invert data using either one-dimensional (1D), two-dimensional (2D) or three-dimensional (3D) approaches. We present a FORTRAN code termed WALDIM to perform the dimensionality analysis of a set of MT data, ac...

Magnetotelluric tensor decomposition: Part I, Theory for a basic procedure

The problem of expressing a general 3-D magnetotelluric (MT) impedance tensor in the form of a 2-D tensor that has been distorted in some way is addressed first in terms of a general theorem. This theorem shows that when the real and quadrature parts of a tensor are analyzed separately as distinct matrices, all that is necessary to make a matrix with 2-D characteristics from one with 3-D charac...

Magnetotelluric Tensor Decomposition: Insights from Linear Algebra and Mohr Diagrams

Magnetotelluric tensor decomposition: Part II, Examples of a basic procedure

The decomposition procedure suggested for magnetotelluric (MT) data in a companion paper is illustrated by examples. Adjacent pairs of stations are examined to test for common features in their MT response. The method analyzes the real and quadrature parts of an impedance tensor separately, and the results for the real and quadrature parts are compared, and in some cases combined, at the end. V...