Vox can help with all aspects of MT and CSAMT analysis, as well as integration and interpretation of multiple geological and geophysical datasets

Data QA/QC and processing
MT data are often complex. Vox’s expert analysis can get more value from existing MT data, including:
– Identification of, and where possible removal of, instrument and cultural noise from MT time series data
– Processing from time series data to MT sounding curves
– Analysis of MT apparent resistivities and phases to identify any systemic instrumentation errors, bad sites or noisy period ranges
– Determination of regional electrical strike and how the preferential current flow changes laterally and with depth
– Calculation of electrical dimensionality for each period at each station. This information is required for an accurate inversion approach.
Survey design and target resolution
– What station spacing do you need to image your target?
– Should your survey be in a profile or a grid?
– What acquisition specs should your contractor be using?
– Is your target even going to be visible with MT?
Before you start collecting data, Vox can help you optimise your survey parameters to give you the best chance for success. By forward modelling your target, we can determine the best station spacings and locations, the required data frequency range, and give you an expectation of how the data will need to be analysed and modelled in a 2D or 3D scheme).
Through integrated rock property assessments, Vox can calculate the expected MT responses of different targets and advise on the optimal survey plan.


1D, 2D and 3D inversions
For reliable results, MT data must be inverted with the right inversion scheme.
When looking at a flat-lying sedimentary basin, fantastic detail can be gained from a probabilistic 1D inversion. On the other hand, when looking at a complex subsurface with conductors running in varying directions, only a 3D inversion will produce an accurate model. One great benefit of MT is that the data themselves can tell us the electrical dimensionality of the subsurface and the direction of current flow. Vox can:
– Analyse MT data to make maps of current flow direction and determine dimensionality for reliable inversion.
– Run 1D models of flat-lying regions, including probabilistic 1D models that are very powerful for depth to basement analysis.
– Determine which subsets of data are electrically 2D, rotate to 2D strike direction and produce 2D inversions.
– Produce fully 3D inversions using the full MT impedance tensor, incorporating topography and bathymetry.
– On all models, run resolution tests, sharp boundary tests and tests of specific features of interest from other datasets.

Mineral systems analysis
In her research, Dr Kate Selway has developed many of the models that underpin the interpretation of deep MT signatures. Vox are uniquely skilled in integrating MT and other geophysical data into lithospheric-scale mineral systems models. By considering geological processes and expected mineral assemblages associated with mineralisation from the base of the lithosphere all the way to the deposit, Vox can build integrated geophysical mineral systems models to help clients:
– Take advantage of pre-competitive datasets like AusLAMP and USArray for terrane-scale greenfields prospectivity mapping of different commodities
– Develop integrated geophysical interpretations of known deposits to improve understanding of ore-forming processes from the lithospheric- to prospect- to deposit-scale
– Produce exploration models for different commodities and deposit types to know what geophysical signatures to expect from the lithospheric to prospect scale.