We have developed a number of software packages for EM data processing, analysis and interpretation.

MT-Corrector software

MT-Corrector software is a convenient and friendly tool for the observed MT responses viewing, editing and spline-fitting. The software has a well-developed GUI with lots of functions. The MT-Corrector could be an important part of any MT interpretational system.

The necessity of the MT responses spline-fitting is caused by the fact that the frequency dependencies of impedance tensor and tipper components are often not smooth and contain outliers. The latter could be a severe problem for the analysis, correction and interpreting of the data.

Main capabilities of the software, that allow the user:

• To overview the curves (frequency dependencies) of impedance tensor and tipper vector components;
• To combine the separate (in frequency) curve segments;
• To delete the outliers, basing on various criteria;
• To add the reference points, basing on the noise charactheristics;
• To create the spline fits of the observed MT response curves, providing the trade-off between small misfits and maximal smoothness;
• To calculate the synthetic phase curves from apparent resistivities basing on dispersion relationship;
• To multiply apparent resistivity curve by arbitrary factor and to invert and shift the phase by 180 degrees.

MTS-Prof Software

MTS-Prof could be used for the MT data visualization, analysis and static shift correction. It supports both 2D and 3D observation geometry. The visualized plots could be exported directly to Golden Software Grapher/Surfer applications.

The static shift correction procedure is realized through spatial smoothing of the amplitudes of impedance tensor components at selected frequency (period). There is a possibility to perform automatic and manual correction.

A variety of visualizing capabilities enables to plot apparent resistivity and impedance phase distributions along with different invariants of the impedance tensor and tipper in the form of pseuodosections, graphs, curves of frequency dependence, polar diagrams and induction vectors.

MTS-Prof is successively used by NORD-WEST for the data analysis before their inversion.

MTS-Prof INV Software

MTS-Prof INV is an inversion tool closely connected to the MTS-Prof package. It is designed for 1D automated MT-data inversion for both 2D and 3D observation geometry. The software uses 1D solver and provides apparent resistivity and impedance phase inversion accounting for the data error bars and stations geometry. An a-priory information on conductivity distribution model could be also accounted for.

The inversion is based on the construction of Tikhonov's regularizing functional and its subsequent non-linear minimization. An a-priory information on the model properties could be introduced into inversion both in the deterministic and probability estimates.

In order to provide the automated input of the inverted data and their dynamical modification a special script language is used. The capabilities of the language allow to create a self-learning inversion scenery wich could be efficiently applied if no a-priory information is available.

The software's GUI is designed for plotting, analysis and selection of the resulting model at any site and iteration. A number of extended facilities is provided for export of model cross-sections and maps, integrated conductivities and data misfits.

MT1D Software

The MT1D software package is designed for the 1D interpretation of the magnetotrelluric (MT) profile data. It has a well-developed multifunctional GUI providing the possibility of manual and automated inversion of the MT responses (apparent resistivities and impedance phases) along with the analysis and visualization of the response pseudosections and reconstructed geoelectrical model.

FS1D Software

The FS1D software is designed for modeling and inversion of the controlled source electromagnetic (CSEM) data in frequency domain (FD). It allows to calculate all the components (Ex, Ey, Hx, Hy, Hz) of the low-frequency EM field excited by the dipole source (horizontal electric dipole AB or vertical magnetic dipole Q) located on the ground surface of the horizontally layered medium. The solver accounts for the medium chargeability. The software provides computational accuracy of about 1% in a wide range of frequencies, offsets and medium properties.

The graphic user interface (GUI) works under MS Windows family. It provides a variety of capabilities for geoelectrical model and observed data visualization/edition, modeled response analysis, data fitting, etc. The FS1D software is an efficient tool for the CSEM data interpretation.

Geological Cross-Section Software

Geological Cross-Section (GCS) software is applied for the plotting of the geological cross-sections of print quality as a result of profile EM data interpretation. The software has a friendly GUI and lots of the capabilities. The main advantage is the possibility to create the ready-to-print final plots from the geoelectric models very rapidly without the use of any specialized vector graphics software (Corel Draw or Adobe Illustrator).