3.3.2. Predicted Data

The predicted data files are output from mtz3d.exe and contain the locations and predicted field data. The order of the data points are the same as the observations file. Each block, separated by a blank line, are the data for a particular transmitter/frequency. Thus predicted data files take the format (unless joint MT and ZTEM):


Data Array 1

Data Array 2

\(\;\;\;\;\;\;\;\; \vdots\)

Data Array N


3.3.2.1. Impedance Tensor Data (DATATYPE = MTZ)

Each row in the array contains the elements of the impedance tensor at a particular location separated into real and imaginary components. The units for predicted MT data are (V/A). The columns for this data format are as follows:

\[| \; x \; | \; y \; | \; z \; | \; Z^\prime_{xx} \; | \; Z^{\prime \prime}_{xx} \; | \; Z^\prime_{xy} \; | \; Z^{\prime \prime}_{xy} \; | \; Z^\prime_{yx} \; | \; Z^{\prime \prime}_{yx} \; | \; Z^\prime_{yy} \; | \; Z^{\prime \prime}_{yy} \; |\]

where

  • \(Z^\prime_{ij}\) is the real component of entry i,j of the impedance tensor

  • \(Z^{\prime\prime}_{ij}\) is the imaginary component of entry i,j of the impedance tensor

3.3.2.2. Apparent Resistivity and Phase Data (DATATYPE = MTR)

Each row in the array contains the apparent resistivity and phase corresponding to impedance tensor entries at a particular location. The units for apparent resistivity data are \(\Omega m\) and phase are \(\phi \in [-180^o,180^o]\). The columns for this data format are as follows:

\[| \; x \; | \; y \; | \; z \; | \; \rho_{xx} \; | \; \phi_{xx} \; | \; \rho_{xy} \; | \; \phi_{xy} \; | \; \rho_{yx} \; | \; \phi_{yx} \; | \; \rho_{yy} \; | \; \phi_{yy} \; |\]

where

  • \(\rho_{ij}\) is the apparent resistivity corresponding to entry i,j of the impedance tensor

  • \(\phi_{ij}\) is the phase corresponding to entry i,j of the impedance tensor

3.3.2.3. ZTEM Data (DATATYPE = MTT)

Each row in the array contains the elements of the transfer function at a particular location separated into real and imaginary components. Predicted ZTEM data are unitless with no normalization factor. The columns for this data format are as follows:

\[| \; x \; | \; y \; | \; z \; | \; T^\prime_x \; | \; T^{\prime \prime}_x \; | \; T^\prime_y \; | \; T^{\prime \prime}_y \; |\]

where

  • \(T^\prime_x\) is the real component of \(T_x\)

  • \(T^{\prime\prime}_x\) is the imaginary component of \(T_x\)

and similarly for \(y\).

Important

  • For MTT data, the first line of each data array within the observations/locations file contains the base/reference station location. When forward modeling, the first line of each data array in the predicted data file will contain the location of the base station and fields predicted at the base station. When inverting, the predicted data file will also contain lines associated with the base station, however the program returns nan for the field values.

3.3.2.4. Joint MT and ZTEM Data (DATATYPE = MTB)

In the case that joint MT and ZTEM data are being inverted, the predicted data takes the following format:


MT Data Array 1

ZTEM Data Array 1

MT Data Array 2

ZTEM Data Array 2

\(\;\;\;\;\;\;\;\; \vdots\)

MT Data Array N

ZTEM Data Array N


where the format of MT data arrays and the format of ZTEM data arrays are the same as above.