Peter Debye's work (1909) contributed to the understanding of Mie's solution and introduced the Debye series which utilizes the Debye potentials. This reformulation enabled interpretation of the solution in terms of physical processes. In this manner, the solution was utilized in many areas of physics prior to computational solutions. These works followed the introductory work of Ludvig Lorenz and thus the solutions are often referred to as the Lorenz-Mie-Debye (LMD) theory. The work was virtually ignored until the 1950's and not until the 1970's was it well known. Later work by numerous authors expanded the theoretical solution to dipole sources following the idea of Mie-type expansions and was used extensively throughout many areas of physics and engineering. For small spheres, the problem simplifies and in geophysics early approximate forms of the solution for "small" spheres were provided by James Wait (1951, 1960, and 1969). Of course, this work had limited practical uses until the advent of the computer. Other partial series approximations have also been presented by various authors in geophysics. However, the series is not monotonically convergent which means that the first term or even the first few terms may not correctly estimate the complete solution. While exploring a strong scattering extension to the Born and Rytov approximations for EM scattering, R. Groom and T. Habashy studied how to provide a precise computational solution to dipole excitation for a conducting sphere in the frequency domain. A method was devised to solve the LMD series for a magnetic dipole source up to 200 harmonics and to determine when and if the solution had converged. This solution was adapted for both electric and magnetic dipole sources and for electric and magnetic fields. The method of solution was found to be generally convergent at frequencies below several megahertz. The solution was subsequently in conjunction with a number of other accurate specialized algorithms to study the accuracy of the Localized Nonlinear Approximation (LN) solution and push forward the initial development of this algorithm. This sphere solution has since been used extensively to expand the capabilities of the initial LN solution and its subsequent extensions. https://www.eikontechnologies.ca/resources/technical.php.

The approach that was taken in the 1990's was a generalization to a uniform sphere of contrasting conductivity, permeability and permittivity to a homogenous background for either a magnetic or electric dipole source. The spherical series expansion which follows Mie's techniques for a uniform field but using Debye potentials is not a monotonically convergent series and thus a simple addition of the initial terms does not generally produce a sufficiently accurate solution except in cases of a "small" sphere. It was discovered that the series can be solved for a converged limit by utilizing the starting and ending terms like a rope tied at both ends. Introduced into the solution was examination of convergence and thus the implemented algorithm will not provide a solution in output if the calculated series does not converge for a particular scattering scenario. Comparisons of this Mie approach to scattering by a sphere to the Born, Rytov and the Nonlinear approximations can be found in Habashy, Groom and Spies (1993, JGR, Vol 98). This solution for scattering by a sphere due to a dipole source has been used for 30 years by ourselves and other researchers to study different numerical solution approaches and the nature of EM scattering in general. In particular, it has been used to study the accuracy of quite a few simulation algorithms. As well, it has been used for crosshole RIM studies, crosshole low frequency IP surveys, crosshole FEM studies with small downhole sources, airborne VLF and other experimental geophysical methods. Several papers on this technique may be found at link provided above.

In recent years, we have encountered numerous EM data sets, particularly in exploration airborne and ground TDEM but also ground-based CSEM where responses are clearly due to both conductive and magnetic materials within anomalies. An further long term request from clients was the ability to simulate weakly conducting volume targets as opposed to the response of the surfaces from stronger conductive targets. Thus, extending this SPHERE solution to loop sources became a necessity for interpretation of clients' data. Additionally, several researchers have been interested to use the algorithm for their studies but extended to common sources such as loops and grounded current dipoles. The effects on EM data due to magnetic material whether electric or magnetic fields and for both low frequency (e.g. IP) or moderate frequencies (TDEM, FDEM) and higher frequencies such as for VLF and RIM are threefold. There can be a magnetostatic effect, an effect on induction as well as an effect on the galvanic response (current channelling). The size of the different contributions depends upon the nature of the scattering problem. And, of course, there are the internal interactions between these effects. One study on these issues is available on our website in the technical papers section (Studies on the Effects of Magnetism on the Scattered Responses of Conductors to Inductive Sources, R.W. Groom).

By implementing discretization into multiple magnetic or electric dipoles, we have expanded the capabilities of this algorithm using various numerical approaches to include the use of:

1. Loop Sources: These loop sources need not be at a constant elevation. Loops with a non-constant elevation as for example vertical loops or loops laid upon sloping surfaces are all allowed. This extends the capabilities to simulate vertical loops inside underground mine workings and also for ground EM surveys in areas of significant terrain. While working with loops which are not of constant elevation is a simple simulation for freespace modeling of a thin sheet, the inclusion of a background response is not so simple. Up to this point, all of our simulation algorithms which allowed a background layered response required a flat loop. This capability, we have also extended to our FSPlate algorithm which does provide a background response to be included with the response of the spheres. There is automatic discretization of the loop sources but the user may also take over control of this process.

2. Grounded Current Sources: The new capabilities also allows for such a current source which varies in elevation. This capability can be used to simulate 3D volume conductive and magnetic targets for land based CSEM, CSAMT and gradient IP. But, it also allows for dipole-dipole and pole-dipole IP responses on sloping surfaces. Again, there is an automatic discretization of the source into electric dipoles but the user may take control if desired.

3. Moving and Fixed source configurations: As examples; airborne TDEM, fixed loop or moving loop ground TDEM, borehole TDEM are all supported as well as fixed grounded current dipole sources and moving current dipole sources. Surface grounded sources to borehole electric field and magnetic measurements is also allowed for arbitrarily low frequency. Simulation of VLF with a controlled vertical source is also provided for ground or airborne configurations.

4. Parameters: Arbitrary variations in conductivity, susceptibility and permittivity to the background are allowed. The background may be a whole space, halfspace or layered model. Small and large spheres as well as sources and measurements close to the sphere are allowed. Internal measurements to the sphere are not provided in this version. Using the Cole-Cole frequency model for polarization effects, IP responses may also be calculated as well IP effects in other EM data.

5. Frequency and Time Domain Responses: Frequency ranges from extremely low frequency to frequencies into the low MHz range are generally allowed. If a particular response for a source-receiver-frequency combination does not reach convergence then a no data value is stored to the database for that particular measurement station and frequency. Time domain responses are obtained through our normal Fourier frequency to time domain transform.

6. Licensing: The algorithm with appropriate functionality is included with any suitable license. The algorithm is not sold separately although the source code may be licensed.

LIMITATIONS: It should be noted several limitations that exist in the present implementation. At present, simulation of the fields within the spheres cannot be done in the present implementation. Also, at present, there are no interactions between the individual spheres in a model. Both of these limitations in our implementation will be addressed in future. Another issue which is presently being addressed is the joint simulation of models which contain multiple primitives (i.e. plates, prisms, polyhedra, spheres). For example, at present one cannot jointly simulate a model consisting of spheres and thin sheets. You can, of course, run a model consisting of spheres and a second model consisting of plates and then add the secondary response of the two models as this functionality is provided in EMIGMA. This is a bookkeeping issue and so for fluidity and convenience, we are presently working on this aspect to allow the mixing of primitives and the simulation of the mixed primitive models.

Major improvements have been made to layered earth inversions for these instruments. This has been done for both the Trust and Occam style inversions. New instrument configurations are now supported and one particular new and very useful capability is selectable Inphase and Out of Phase data for each component and frequency individually. This augmentation is due to the presence, on the market, of instruments that now gather quantifiable Inphase data. In addition, alterations and improvements have been made to the freespace plate inversions for FDEM data in particular considering MaxMin and Promis data.

3D Inversion Interfaces:
Interface dialogues have been enhanced and additional inversion options added for all our 3D inversion applications [ Resistivity, Gravity, Magnetics, CSEM, CSAMT ].

Magnetic Data Tools
Work has been done to improve and extend the ability to perform complex model simulations including augmentation to the multi-core and array processing components. The enhanced simulation of magnetic models containing DEM topography allowing for the inclusion of magnetic property contrasts within the topography which is particularly useful in areas of elevated terrain. The 3D inversion tools have also been augmented with issues including; the provision to provide susceptibility continuity across boundaries in the inversion grid when cell thickness changes. Inversion to a constant depth in surveys with high topographic variations has been added, improved cross-sectioning with augmented 2D viewing of the cross-sections, editing of inversion grids to extract critical structures, provision to export extracted grids to CAD format including support for AutoCAD. Other processing issues include the addition of the calculation of derivatives via DFT which uses rectangular grid cells to maintain along profile data resolution and significantly reducing cross line artifacts. This capability now provides significantly increased clean and accurate derivatives over traditional FFT techniques. New extraction techniques have been added to remove extrapolated derivatives outside the survey area particularly for irregular survey lines thus removing artifacts at the edges particularly when using the derivative inversion grids in an inversion. Additionally, we now provide aeromagnetic compensation for drone data and gradient data. IGRF14 has been enabled allowing determination throughout a survey for changes in date, elevation and time.

Filtering tools

New filtering capabilities have been added. These include a data extrapolation algorithm and two interpolation algorithms when data stations are irregularly distributed. One algorithm is for along profile and the other are 2D spatial interpolation. These algorithms can interpolate both your data and your stations positions.

Gravity Data Tools

We have considerably improved the isostatic corrections introducing new simulation techniques allowing for larger and more detailed corrections. These corrections are extremely important in areas of high elevation as well as in areas near ocean coasts and for marine surveys. Additionally, we have added improved bathymetry corrections and added corrections for the effects of marine sediments. These latter corrections being important not just for marine and harbour work but also for island and coast line data.

In terms of the gravity inversions we have augmented memory allocation as well as the use of more extensive and detailed DEM topography in the user model grid. We have also enhanced simulation of gravity models with DEM topography grids and enabled inversion of gravity derivatives to be suitable for airborne tensor systems as well as for DFT derived derivatives from ground data. The derivation of DFT derivatives has been significantly improved particularly in terms of removing edge effects.

Display and Filtering Tools

There are many items in this area of development but some of these improvements include:
- Augmented cross section visualization tools for both 3D and 1D inversions principally for gravity, magnetics, resistivity and CSEM inversions as well 1D stacked TDEM and FDEM inversions
- Extended tools to export models and model data
- Augmented grid information display
- Improved cleaning of DFT processed grids such as derivatives, RTP, upward continuation
- New precision extrapolation removal tools for multi-parameter grids

General Features

- Augmented and improved plotting tools
- Improved changing of system configurations for inversion and simulation
- Enlarged system configuration capabilities
- Changes to controls and interfaces to improve readability and functionality
- Improvements to imports as well as augmentation of imports. Examples include FDEM, VLF, MT, AFMAG, airborne TDEM and the import of AMIRA formatted data
- Improved conversion of one 3D algorithm primitive to another
- Improved editing capabilities of models in a plan section survey display
- added classic Geotiff file export for maps

EM Simulation Issues

In addition to a new algorithm with dramatically increased capabilities, there has been a variety of improvements to older versions of some of the EM simulation algorithms. These include:
- improved accuracy of low frequency background response of magnetic dipole sources
- improved background response accuracies for FD and TD IP models
- improved storage and recovery of Greens functions [ .dmp archives]
- improved background responses for grounded sources - i.e. CSEM, CSAMT, IP
- improved prism/poly simulation when the top of a target crosses near or immediately at a layer interface. Note that in these cases, current flow between the top and bottom part of the target is maintained
- we have enhanced VLF survey configuration tools
- we have added VLF Controlled Source capabilities
- major improvements to simulation of edited 3D Resistivity inversion models

Visualization Additions

Our visualization tools have been improved in order to enable visualization of 3D models and inversions from different survey types. For example, the joint visualization of a 3D resistivity inversion models with an EM model (e.g. thin sheets or spheres) from a borehole survey. Or the joint visualization of 3D focused airborne magnetic inversions with airborne TDEM plate models. These additions include
- Visualization of mixed 3D primitives which allows for visualization of primitives from different algorithms
- Mixing inversion grids with 3D primitives
- Inversion grid editing. This allows to remove, for example, small contrast cells to focus on the more important cells or the removal of cells above or below certain depths or the removal of portions of the inversion volume conversion to CAD formats

New 3D EM/IP Complete and Exact Simulation Algorithm

Additionally, the inversion has been extended to allow up to 10 plates in an inversion model introducing a complexity in interpretation not yet seen in TDEM data.

We now offer this as a service and have had several successful interpretations this year in regard to mining exploration in Canada.

Three Dimensional Earth Models from a ground current source (CSEM)
We have offered 3D inversion of CSEM data applying the source as 3D for some years. But, the previous work was focused on the inversion of multi-component electric and magnetic fields due to the source. However, there is much legacy so-called CSAMT data which has to date only being interpreted assuming plane wave sources which we have shown to be badly representative of structures. In many legacy cases, the electric and magnetic fields cannot be interpreted with a 3D source as the source effects at the transmitter has not been removed. Thus, the only remaining data that can be utilized is the ratio of electric to magnetic fields (impedances). We have made a successful breakthrough in inverting this data.

3D Magnetic Inversion
Our multi-core solutions for magnetic inversion using a linear inversion approach has been very successful not suffering non-uniqueness problems to the same degree as other commercial apps. We have been involved with our clients in the inversion of large scale airborne magnetic data over the areas of high topographic relief (BC Rockies). The magnetic inversion has been extended to offer new capabilities in depth resolution in such environments.

AeroMagnetic Compensation
We have been told many times that our compensation is extremely good and this has been for fixed wing, towed helicopter and stinger applications. We have now extended this capability to drone data allowing compensation using custom calibration flights at the maximum heights allowed for drone operations (typically 200m)

In EMIGMA, a non-interacting layered background was enabled some years ago to allow the inclusion for weathered and conductive cover during interpretation as well as an only moderately resistive host. This app allowed for utilizing either a direct in time domain solution for the plate or a frequency to time transform solution if the bandwidth was critical to interpretation. The forward application is also provided for FEM data.

This latter version is the forward basis of Eikon's plate inversion app which allows both TDEM and FDEM data. In the app, for TDEM, the user may select the two types for forward approaches and the band width in the transform version. The background field is to be set by the user (see suggestions below) and the inversion is then performed on the secondary field. If no background is required then this is allowed. There are two completely different inversion algorithms provided. The first is based upon the traditional simplex approach and the second our well used and proven Trust Region approach.

Multiple sources and multiple receiver components are allowed and each TX-RX component may have its own selection of time windows or frequencies. The user may also select for each component the portion of the survey which will be utilized in the inversion. All of this may sound more elaborate than necessary but we have been developing and testing the application for more than 3 years now and many implementations were found necessary while testing with survey data from surveys around the world. Some implementations are made specifically for certain specialized survey configurations.

The application is enabled for ground, borehole and airborne data and allows for up to 6 plates in the inversion model. We suggest using our forward and inverse 1D modeling for setting the background. The 1D inversion allows to invert for a best 1D model for many stations which is very practical when working particularly with airborne data. We also suggest some preliminary forward modeling to utilize as starting models in the inversion. All parameters of the plates may be constrained.

We tested the software on data from a wide range of equipment for ground, borehole and airborne surveys. We have waited for release until we had sufficient experience utilizing the app in our consulting work for the past six months. For airborne data, we have utilized it for VTEM, Xcite and SkyTEM all collected within the last five years.

We now offer this as a service.

One Dimensional Layered Earth Models from a 3D source
These algorithms are fundamental to all of our EM algorithms and inversions including IP, Resistivity, CSEM, FDEM and TDEM. Not only do they provide the background fields for the computations but for algorithms which provide interactions with the background, they produce the Greens functions to produce the secondary fields at the receivers due the buried structures.

We have made a huge leap in the accuracy and speed of these computations. This affects such things as receivers near a loop or grounded wire as well as receivers near 3D models. Also, this improves the accuracy of low frequency calculations as well as receivers far from the source of the secondary fields. With regard to computation speed, in many cases, computation times are dramatically reduced due to the user of multi-cores and other computation aspects of the new generations of CPU's.

3D Magnetic Inversion
The new generation of processors such as the AMD Ryzen processors, extend substantially the potential size and speed of inversion applications. Our inversion applications including the magnetic inversion utilize a direct matrix approach rather than the more common "hunt and seek" approaches. Therefore, we have upgraded this algorithm to enable much larger inversion problems.

For example, our FFT and DFT algorithms for generating derivatives produce a very accurate vertical gradient. Combining this gradient with the total field produces better depth estimates from the inversion but requires an increased size for the inversion app. Also, drone surveys produce much higher spatial resolutions and can sometimes produce very large datasets larger than towed or stinger helicopter surveys. These developments have required us to enhance our magnetic inversion app to handle such situations. Additionally, new magnetic vector drone surveys can be even larger.

We will soon be adding inversion capabilities for borehole magnetic surveys which will lead to the ability invert borehole data with ground and/or airborne data. At present, you can jointly invert your ground and airborne data.

CSEM Processing, Modeling and Inversion
We have augmented our 3D CSEM inversion in our EMIGMA V11 release.

We continue our work on land based CSEM to provide a comprehensive set of tools to allow proper processing and interpretation of geophysical surveys with a grounded transmitter utilizing both magnetic and electric measurements. This includes proper processing and interpretation of so-called CSAMT.

Along with these developments, you have been able for the past few years to utilize our 3D inversion allowing for: a) multiple transmitters b) multi-component magnetic and electric measurements without the need to contract to an impedance and c) many receivers on multiple survey lines. The inversion is multi-core and utilizes array processing techniques and new techniques in inversion.

The non-linear approximator (LN) algorithm offers improved results in areas of high background resistivities. Most electric field inversion applications only provide a Born scattering approach whether intentionally or not. In V11, we have reached out more towards the full potential of this algorithm in an inversion app. The algorithm is very fast and accurate for forward results but applying this approach to inversion is not as straightforward as it may seem. Thus, we are happy with our progress in this direction and find it now much more useful in our consulting work.

Visualization
EMIGMA is constructed upon a relational database structure. As such, it was intended for joint interpretation of multiple data types. As the inversion techniques have improved in their usefulness, it has become necessary to improve the visualization inversions as well as integration in the visualizer of inversions and models from different types of survey data. For example, visual integration of IP and TDEM models with magnetic inversions. It has also become necessary to improve the speed and stability of visualization large inversions.

We have also added processing of inversions in order to reduce the inversions to the critical portions for visualization in EMIGMA as well as export to CAD models for the geologists. We have also added the ability to produce cross sections for viewing in EMIGMA and depth sections for viewing in QCTool.

There have also been improvements and extensions to our 2D section viewer, Survey Editor viewer and Grid Presentation tools.

Details of QCTool upgrades may be found on the QCTool website qctool.ca.

More than 2 years of development have gone into the upgrades in EMIGMA V10. These notes will cover some of the changes.

Magnetics
Our 3D gridded magnetic inversion has been augmented in several aspects. The application already was a multi-core, array processing application but has been upgraded to allow a larger set of data as well as a much larger number of cells in the inversion grids. The inversion now allows the import of the topography over and in the vicinity of the survey. This is critical not only for accurate depth determination but also to address features within the topography. We have also upgraded the ability to introduce known magnetic information either for surface sampling or borehole cores. We have also upgraded to allow the use of CAD models as starting models for the inversions. Joint inversions are now allowed. These can be multiple data components such as the TMI and one or more of its derivatives. Also, joint inversion of airborne and ground data is now provided.

In some instances, magnetic anomalies may conform to Poisson's relation and in which case, it may be interesting to joint invert your magnetic and gravity data. To address this situation, we have added another option to import as a starting model, your gravity model or inversion and vice versa in a gravity interpretation project. In this case, when using a gravity anomaly or grid as a starting model, the software will use Poisson's relation to accurately determine the relation between the density values and produce susceptibility values for the starting model. The reverse is done in the case of gravity interpretation.

EMIGMA has long offered the simulation of models for magnetic vector data. We have now released our 3D gridded inversion to provide 3D inversion of vector data. Vector data must normally be processed prior to inversion and these processing capabilities are now released in our latest version of QCTool(V5.0). First, the vector components must be organized so that they are in a consistent orientation. Now that most instruments have IMU capability, we can now rotate the vector data to a consistent grid orientation. Two choices for grid definition may be made by the user, either geographic north or a user defined grid azimuth. Additionally, QCTool now allows the calculation of the derivatives both of the TMI and of vector data if multiple sensors are present. These gradients must also be de-rotated prior to inversion.

Additionally, in our magnetic tools we have upgraded the magnetic compensation to allow several new capabilities. First, compensation may be done on either TMI or vector data and the compensation coefficients may be calculated using either standard vector data or IMU orientation data. Finally, we have made what we believe is a significant break-through in the sense that high altitude box data is no longer required. Relatively low altitude data such as at 200m can now be used for the compensation coefficients. These new features make the compensation processing of magnetic data for either drones or UAV very accurate and efficient.

TDEM
Major upgrades have been made to handle multiple data sets primarily to deal with the issue of strong non-uniqueness of inloop inversion models and the dangers thus presented. To address the non-uniqueness and inaccuracies in depth determination from inloop data, we have provided multiple component inversion for some time. This includes horizontal as well as vertical data and the use of data at any position from the center of the loop such as out of loop data and data in the loop but not at the center. The new capabilities allow such configurations as ground and airborne data as well as data sets with different loop sizes and base frequencies. We have demonstrated that with the use of two loop sizes, two base frequencies and inloop and out-of-loop data that one can determine a unique 1D model with accurate depth and resistivity information if in the appropriate environment.

Visualizer
EMIGMA has had 3D visualization tools for many years in order to build forward models, examine CAD models and provide some forms of data examination. In recent years, we have provided in our visualization application, the means to examine, in detail, the user's inversion models. These tools allow the user to slice the inversion at various depths and across sections as well as examine inversion results in terms of inversion cell parameters. However, users have long found the application unstable when working with complex models and large inversion grids. Major advances have been accomplished to address these problems and provide significantly faster and more stable viewing.

Resistivity
EMIGMA's 3D resistivity forward modeling algorithms are arguably the most comprehensive, rapid and accurate available and these capabilities give us strong advantages when developing inversion algorithms. Resistivity forward and inverse algorithms are now available for both moving systems (dipole-dipole, pole-dipole, pole-pole, Xhole) and fixed source surveys. For fixed source, EMIGMA offers algorithms for ground as well as surface TX to borehole RX and borehole TX and surface RX.

Both the forward and inverse algorithms are integral equation approaches. This provides significant advantages for both accuracy and speed. With an IE technique, there is no need to extend the grids to "infinity" to meet boundary conditions. The boundary conditions are automatically met by the inclusion of the background layered model that hosts the forward and inverse grids. But this approach offers other helpful techniques when performing inversion. For example, once an anomalous area is identified, the inversion grid may be focused onto that area to delineate the structure.

EMIGMA's inversion algorithms in V10 have had a number of upgrades. One of the most important upgrades is the addition of a non-linear forward solver (LN). Electric, such as observed in resistivity surveys, is one of the strongest scattering phenomena observed in nature. Resistivity contrasts across boundaries can be orders of magnitude and this is reflected in electric field current scattering contrasts across the boundary but current bending and gathering is also an important and strong feature in resistivity data. It has long been shown that standard solvers for electric field scattering are not able to both represent the amplitude of the electric field contrasts nor force the current bending caused by current being divergent free and subsequently the interactions between cells. One initial objective of the EMIGMA project was to address these issues and we have solved many of these issues in our forward algorithms but we have now introduced some aspects of these solutions to the inversions. Additionally, the resistivity inversion has been upgraded accordingly: upgraded to handle larger problems in terms of the size of the inversion grids and the amount of data, upgraded to multi-processing and our new techniques to handle memory issues more efficiently, upgraded in the case of fixed transmitter surveys to handle multiple transmitters as well as multiple orientations of voltage measurements, upgraded to allow the inclusion of geological constraints and to allow both polyhedral and prism starting models.

CSEM
3D CSEM/CSAMT inversion: upgrades include allowing more multiple transmitters, more data components (electric and magnetic data) and a larger frequency suite. Also, included is a non-linear forward component allowing resolution of more high contrast structures. Improvements have also been made to improve speed and stability as well as new starting model capabilities. In QCTool, we have upgraded to allow processing of raw data from full waveform time series to generate the impulse responses for the field data.

Gravity
Important upgrades to gravity processing have been made in QCTool for the isostatic effect. This is a critical correction if topography corrections are required. Topographic corrections must be adjusted for the isostatic effect as over high elevation areas, topographic corrections remove too much of the field and over low areas or on the sea, topographic corrections add too much into the field. The isostatic correction offsets these excessive corrections. This is one reason why performing Bouguer corrections may not be the correct approach for you.

One way to deal with the uncertainty concerning whether to perform Bouguer(terrain) corrections is to introduce the terrain into the inversion problem. In this way, variations in density in the terrain may be considered and shallow anomalies in the terrain may be resolved. In EMIGMA's gravity inversion, the user may import a digital elevation model into the inversion process. In this way, targets in the topography may be studied but also depth to targets will be more accurate than if everything is leveled to the geoid.

Additionally, the gravity inversion has been upgraded to allow polyhedral starting models as well as prisms. This can be used to introduce contact surfaces if available from either drilling or seismic work. Geological information may be introduced into the inversion.

Fourier Processing
Deriving a frequency spectrum for full wave data via FFT techniques is limiting due to the requirement for the time series to be of length 2^N. This is particularly true when trying to recover the phase of a spectral (frequency) element. We have discovered with some manufacturers that the phase estimations can be terribly inaccurate for some frequencies. We have developed processing tools in QCTool to allow the user to process full waveform data whether EM, CSEM or IP via DFT (Discrete Fourier Transform) techniques. Historically, although this approach is known to be more accurate, geophysicists have relied on FFT due to computation times. To address the computation time, we have made the DFT spectral analyses and filtering algorithms multi-core, multi-processing which now makes this approach practical on modern computers running Windows.

FFT techniques are also used for processing potential field data for such targets as derivatives, wavelength filtering, upward continuation, and reduction to the pole. We have implemented our DFT algorithms for such processing. This improves the feature resolution as the cell size for calculating the Fourier processes is now not limited. In particular, this removes crossline artifacts and their effects on the vertical derivatives and thus all types of Fourier processing.

Thus, there is a need to simulate (forward model) the effects of contrast between host and anomaly, not just the conductivity and permittivity but the magnetic susceptibility. We have augmented our algorithms to compute the first and second effect mentioned above allowing the 3D objects (prisms and polyhedras) as well as the background layered field to have susceptibility different from freespace.

Augmentation of Processing and Filtering Algorithms
Digital Fourier Transforms
Fast Fourier Transforms have long been used in geophysics. However, they lack the accuracy and precision of DFT's and with modern computing techniques there is no longer the need to use the quick, approximate FFT techniques. We have enhanced our DFT tools (spectral analyses and decomposition as well as filters) to provide extremely highly accurate computations in both amplitude and phase. And, we now can handle extremely long time series as the algorithms are multi-processed.

Processing of towed multi-sensor magnetometers
These enhancements pertain to both total field as well as component sensors such as fluxgates. Our compensation algorithms have been enhanced in quite a few areas. First, we enhanced the algorithms to deal with component data and second, to compensate gradient data. Often as it happens it is much better to first calculate the gradients and then to compensate these gradients rather that the processing in the opposite order. These gradient enhancements are also for component data. Other enhancements in magnetic data processing are the de-rotation of component data where the components of the magnetic field or the components of gradient data.

TDEM Inversion
Our inversions for TDEM still pertain to 1D models. However, we have enhanced the capability and accuracy of our Multi-Component, Multi-Station inversion for both our overparametrized, smooth inversion (Occam) as well as our underparametrized Trust Region technique. The latter technique is not a linear technique as the inversion algorithm does not stop at the stage of using the Jacobian. These tools are very useful in reducing the non-uniqueness issues in TDEM inversion.

CSEM Processing, Modeling and Inversion
We continue our work in land based CSEM to provide a comprehensive set of tools to allow proper processing and interpretation of geophysical surveys with a grounded transmitter utilizing both magnetic and electric measurements. This includes proper processing and interpretation of so-called CSAMT.

We continue to advance the processing of raw time series to produce the required impulse responses in the frequency domain for two component electric field measurements and three component magnetic field measurements.

With these processing capabilities linked to our forward modeling and inversion routines, you may now collect, process and interpret such data without the need for large spatial offsets in the transmitter and receiver.

This, of course, has many benefits both in cost and operational activities. There is now no need for huge, heavy and expensive transmitters. Very long transmitters with very large distances to the receivers are now no longer necessary. Interpretation is now much more straightforward as you no longer have to concern yourself with such things as: a) being in the far field b) transmitter response at the transmitter site and c) response of the intermediate region between transmitter and receiver.

With this new processing, you will now be ready to utilize our ground breaking 3D inversion allowing for: a) multiple transmitters b) multi-component magnetic and electric measurements without the need to contract to an impedance c) scalar or vector measurements d) many receivers on multiple lines ( profiles). The inversion is multi-core and utilizes array processing techniques and new techniques in inversion. Actually, not new but we have gone back to the fundamentals and play no tricks in the inversion process.

In this resistivity inversion our approach is unique from several perspectives.

First, our mindset is that finding models to fit the total or entire response is a simple inversion problem; not spatially selectively accurate and prone to non-uniqueness. This non-uniqueness is caused by the general approach to gridding the entire ground which thus extensively overparametrizes the inversion ( i.e. more model parameters than data). Therefore, our approach is to estimate the background resistivity model with a layered earth and then to invert for only the secondary fields constraining both the volume of the inversion and the resistivity in the inversion model. We have found in our experiences with many of our clients’ datasets that the estimated background resistivity is fairly easy to define and can be accomplished easily with our layered earth inversion utilizing all transmitters and receivers to obtain a uniform 1D estimate containing possibly multiple or many layers to define the hosting resistivity and for all the data.

This approach then allows for an iterative approach to focus on the anomalous region and thus detectable targets. We utilize the ability to define the inversion search volume as specified by the target focusing ability of the multiple transmitters. An initial course inversion provides an indication of the direction of the anomaly and its depth. Then the inversion volume can be re-defined easily to focus on the appropriate region. These techniques are efficient in finely delineating the targets.

The inversion itself uses multi-processing to utilize all the computers resources. With the recent versions of Windows and the new CPU’s there are now almost always available a number of processors. Additionally, the new compiler capabilities are much more accurate and quicker although requiring much tighter software. The multiprocessor compilations are very stable while not taking over completely the computers resources allowing you to continue utilizing your computer for other uses if needs be.

Additionally, with these techniques there allows the matrix defined by the sensitivity functions of the transmitters to be inverted directly using array processor technology. These processes are very stable computationally and remarkably fast. These inversion capabilities are augmented by exceptionally accurate techniques to compute the forward models and the model gradients.

Functionality has been included to provide:
Stacking and Windowing
Our stacking routines for repetitive periodic data has been augmented and particularly to add a standard bipolar waveform for the stacking. Windowing of a raw time series to create time windows from the time series. A predefined file containing the window specifications may be read to create the windows.

Geophysical Processing
Two types of tie line leveling have been added to the potential field processing tools. Magnetic compensation utilizing orientation data has been enabled. De-rotation of derivatives has been provided utilizing orientation data. Derivation of Cole-Cole parameters has been enabled for both frequency domain and time domain IP data. IGRF calculations have been extended to include time as well as location and date. The WMM2015 model has been added for background magnetic computation.

Digital Processing
Our FFT and DFT has been extensively upgraded both for speed and accuracy. Complex arithmetic is now provided in our calculator tool for computing channels.

Spreadsheet Functions
A number of new functions have been added to the spreadsheet tools and other tools improved such as duplicate averaging, outlier removals and filtering

Grid Tools
We have added a windowing tool in the QCGrid tool to select or remove a polygon window.

Bits and Bobs
The opened file is now automatically backed up, geospatial information can be added to exported maps in pdf format, your previous gridding settings are saved to the data file for later use as well as a wide range of improvements and additions to PEGEOMAP.

For aeromagnetic data, the processing and compensation is suitable for fixed wing, helicopter sting and towed systems and for drones. The processing allows to work with single or multiple TMI sensors as well as 3 component magnetometers including fluxgates.

The compensation is now enabled for the use with either fluxgates or IMU's, thus allowing for compensation and interpretational use of fluxgate data.

New tools include the calculation and de-rotation of gradients. Thus, the IMU data can enable compensation of your multiple TMI sensors and thus calculation of gradients in the vehicle coordinate system and then de-rotation to either a grid azimuth or magnetic or UTM north. But, what is most exciting is that we can now compensate fluxgate data and then de-rotate the component data to a single coordinate orientation thus enabling modeling and inversion of the fluxgate data providing a whole new power to aeromagnetics.

These tools add to an already impressive list of processing capabilities including the derivation of processed gradients using our advanced Fourier techniques otherwise not available in any other product.

The tool also has an impressive list of mapping capabilities as well as the most advanced filtering tools in the industry.

Easy to use and easy to interact with other software products.

The basic license is $5,000US which includes a full license including calculation of compensation coefficients and compensation of data and another license to use compensation coefficients and compensate your data.

Only compensation of data is available through a GX.

We are pleased to announce the release of V9.5 effective October 5, 2017.

CSEM
This past year, we have completed our procedures to enable the use of Land Based CSEM survey interpretation. These survey strategies are based upon marine CSEM with some important differences. Here, as well, the transmitters are long grounded current sources generating responses not only due to the injected currents but also due to induction from currents along the wire. Thus, this is truly an EM technique. Our application allows for the collection of dual orthogonal voltage receivers and 3 orthogonal magnetic receivers or any subset of these receivers without one or more elongated voltage transmitters. The applications allow for data in the frequency domain with inphase and out-of-phase data or both.

The tools provided include a full range of processing, editing , plotting, mapping and visualization tools as well as 3D and 1D, forward model simulation and inversion procedures. The 3D forward model tools are built upon our last few years of work to provide accurate simulations for a range of survey types using grounded sources including both borehole and ground surveys at low and high frequencies. The inversion tools are extensions of our 3D source tools for CSAMT.

At present, we are modifying the land based CSEM to handle marine CSEM. In this regard, we are offering a free license with 1 year maintenance to the first university who provides us with marine CSEM data.

CSAMT
The CSEM tools are also integrated into the CSAMT capabilities although with some limitations but also allowing for the inversion of impedances as well as fields. Thus, the new tools may be used effectively with old data to allow you to finally interpret this data correctly without the very limiting limitation of using the so-called far field techniques.

MMR
This year with our research on the accurate simulation of grounded current sources, we have also upgraded our MMR tools. These new tools are available for both borehole and ground surveys allowing also for sources to be configured in boreholes. These tools allow for a complex multi-point location of your sources on surface or underground and new tools for allowing for a multi-layered host. We have upgraded our tools to allow for complex structures including import of your CAD models. Time Domain EM For our time domain tools, we have further extended an improved our constrained multi-component and location TEM inversion. This allows full flexibility with either moving loop or fixed loop surveys as well as providing good moving window tools for airborne TEM. You will find some examples of papers on these methods in the download technical section of our website. For those working in resistive environments, we have continued improvements on our inductive plate algorithm. This algorithm allows correct loop configuration, system response and includes the response of the host material allowing one to accurately and very rapidly model our TEM targets. Of course, this tool can be used in airborne, ground or TEM surveys. It is important to understand that the algorithm calculates the current distribution rather than simply applying a simple target centered set of dipole currents. Thus, the algorithm accurately simulates your early and late times with the correct migration of currents. You will find an interesting study on our website comparing our algorithm to another popular but limited algorithm.

Magnetotellurics
Principally, in this aspect, we have made a range of improvements in the tools to display and analyze results. But, there are important improvements to both the 1D and 3D inversion tools. Improvements have been made to the decomposition tools and this software is included in an MT license.

Gravity 3D Inversion
The topographic survey and structural horizons including the basement are important aspects of gravity inversion. The new gravity inversion tools allow you to construct these horizons and utilize them in your inversion process. This is an important aspect in resolution in gravity inversion. The ability to invert within the topography can be important in some surveys.

Other Functionality
There are a range of other new capabilities which have been added. Some of these include the ability to create kml files to import surveys or grids to GoogleEarth, the ability to import or export 3D .dxf for modeling purposes in addition to the other CAD formats previously allowed. We have now provided the ability to export 3D pdf both for your models, inversion grids as well as data surfaces. This is in addition to exporting scaled 2D .pdf.

We now provide a full range of marine potential field processing and interpretation tools.

3D Induced Polarization Modeling
While 3D and 2D inversion has become popular, we are still restricted as popular inversion algorithms use approximations for the forward simulation of iterative models required in the inversion process. Additionally, we still require modeling for planning purposes and to understand IP and resistivity responses. Also, we do require the ability to completely simulate the entire IP response which requires multiple parameters to characterize an IP anomaly.

Petros Eikon has always considered integral techniques the only satisfactory means to provide 3D simulations. This is for a number of reasons and not least that IE models are the easiest to build with a suitable visual interface. The building of complex models in a defined finite difference or finite element scheme is too time consuming if the user wishes to execute numerous models easily and quickly. The other principle reason is that proper IE algorithms remove many of the weaknesses if forward simulation when the data locations are near the anomalies.

While, we have provided fairly comprehensive 3D IP modeling for almost 2 decades, our recent developments to provide even faster and more accurate 3D resistivity modeling lead us to wish for such improvements for our IP modeling. This instigated several years of development to provide such capabilities.

The new release provides more rapid and accurate computations for a full range of survey configurations including surface dipole-dipole, pole-dipole, gradient, Schlumberger and Wenner arrays as well as surface to borehole. These solutions are for real world transmitter and receiver configurations and not just point dipole setup. The model specifications can include a many layered background wherein any layer or multiple layers are polarizable and all 3D targets may be polarizable or non-polarizable. The simulations provide complete interaction physics between layers and targets and between targets.

1D TDEM Inversions – Extensions for Multi-Component Data
Inversion of TDEM data was introduced in EMIGMA more than 10 years ago with some unusual capabilities! The app could invert not just the vertical vector component of the magnetic or time varying magnetic data at the center of the loop but also data outside the transmitter loop as well as other vector components. Later, for fixed loop data, we extended these capabilities to allow simultaneous inversion of multiple components as well as data at multiple data sites both inside and outside the loop. Since EMIGMA had contained very accurate layered earth forward modeling for many years and for a wide range of survey styles, it was not difficult to apply an appropriate inversion technique to these long standing forward capabilities.

For moving loop data, we later introduced the idea of different components. A component was defined by a combination of the [tx-rx] separation vector and the magnetic field vector component. Inversion was offered utilizing single or multiple data components and later this was extended to use multiple loop locations when required. To compare to standard TDEM inversion functionality on the component with zero separation and the vertical field can be utilized.

The need, both practical and theoretical, to extend these capabilities has continued to grow and with larger and larger amounts of data components to be utilized in the inversion. With these expanding requirements a need to increase speed was also much required. An obvious example of such a need is for inversion of Step-Wise Moving Loop data where it is not uncommon for more than 30 separations to be available for interpretation. These components consist of a wide range for separation distances from inside the loop to distances at times more than a kilometer. With standard TDEM windowing, this can introduce more than 600 data for the inversion thus requiring a very complex model even for an underparametrized inversion.

EMIGMA’s TDEM inversion app has from the beginning contained both overparametrized and underparametrized model capabilities with constraints allowed on all model parameters. These fundamentally important requirements have been maintained even as we increase the number of data parameters as well as model parameters in both inversion styles.

PseudoSection Viewer for 1D Inversions and 3D Inversion Cross sections
EMGIMA’s 2D cross section viewer app has undergone a major overhaul this year. Many annoying small problems have been corrected and a number of new capabilities have been added. But, the principle improvements are in the speed and accuracy of the graphic displays and in general, being visually pleasing.

Improved interpolation techniques were introduced and new methods to display graphically the results. This tool like many others in EMIGMA is designed to deal with multiple lines of data as well as inversion parameters. The transitions from line to line are now more rapid and more straightforward for the user to employ.

For over 20 years, we have dealt with land based injected current source surveys for electric and magnetic fields, in both frequency domain and time domain.

We are the most experienced developer for land based controlled sources of any kind for surface or surface to borehole surveys.

Our techniques are fast and with 20 years of proven accuracy built on a full database platform with smooth operating interactions.

Traditionally CSEM software is priced for the oil and gas industry whereas ours while serving O&G, mining and environmental clients, are priced so all these sectors can afford our software.

A complete description will not be given here but one can refer to the tutorial and our new publication for some more details.

First, to better compute an inversion model for moving loop data whether on the surface or in the air, we have added further capabilities such as: if your data has only one component (.e.g. Hz or Bz) and only a single separation (e.g. inloop), then you can utilize a moving window to invert multiple datapoints along your profile. If you are lucky to have multiple components (e.g. Hx as well as Hz) and multiple separations such as data outside the loop, then one can jointly invert multi-components and/or multi-separations. This ensures not only a deeper resolution but is much less likely to be subject to non-unique solutions. Each component and each separation has, if necessary, its own time window controls. The inversions still provide extensive model constraint capabilities as both underparametrized (for depth resolution) and over-parameterized (smooth) inversion capabilities are provided. The system waveform details are utilized in the inversions as are the instrument’s frequency bandwidth.

Also, included with this release is another revolutionary feature: the ability to use multiple base frequencies when inverting the data. Often, ground TEM data is acquired at multiple frequencies including at lower frequencies in order to be able to see ‘deeper’ due to the longer measuring period. However, up until now, the user was forced to invert data from each base frequency separately and then analyze the result manually. With this new feature, one may invert multiple data sets acquired at different frequencies, all at the same time.

For fixed loop data, inversion capabilities include use of a moving window along profiles or defined multiple stations. Each of these capabilities is allowed multiple data components and provides time window controls. The need for such capabilities may seem odd to some readers but we have required all these tools in our consulting service and have originally developed them for this purpose. Having used these techniques internally for several years, we are now releasing to all our users.

Finally, we have added the ability to utilize multiple base frequencies in the inversion process. While this has been popular for some time in other software due to the users misunderstanding that this can provide a deeper resolution, we have not found it necessary for our use. However, over the last year, we experienced data from a system which has poor current turn-off controls and found that in this case, such a capability can be useful. Additionally, from a theoretical perspective, this capability is useful to enlighten us on the danger of inloop measurements for inversion.

Our inductive plate algorithm is based upon the theoretical formulation first made by Peter Annan in his PhD thesis. This formation was later implemented in what was for a decade or more called UofT plate. Although, our mathematical formulation is little modified from the Annan’s original mathematics, the numerical implementation is far different from the older implementation. Additionally, the implementation has been augmented to incorporate both traditional and modern current waveforms for a variety of systems as well as our methodologies to incorporate other aspects of the instruments’ impulse responses have also been included.

The implementation is not just for a simple induced dipole current as in some other popular software but rather a system of eigenfunction expansions of the current. This expansion of the induced currents allows for among other things, the ability to have large gradients of the source field over the object and to allow plates with very different aspect ratios—issues which are critical in accurate modeling of airborne TDEM data. Additionally, the implementation allows the user to have multiple targets and to implant these targets in a layered earth model by superposition of the inductive response of the plates with that of the background earth.

In our new release, we have implemented a new compiler and implemented other engineering aspects. With all of these changes, the result is up to 50 times increased speed of computation!

The current developments will move the implementation to a multi-processing application which will allow for increased speeds, depending on the number of processors available.

Support for CGG 100% normalized step response data has been implemented and is released in today's updates. The CGG systems are based upon the older South African Fugro systems. The data is collected in the off time of a 50% duty cycle and then is processed by various steps to 100% duty cycle reduced by the primary field and normalized by either the primary field (freespace) or a late time channel. EMIGMA supports both the 225Hz system, termed Genesis, and the 90Hz system termed, TEMPEST. Data may be imported for several configurations and specific system aspects are defined for storage to your database. From there, you may work with the data as any other airborne TEM system. 1D and 3D modeling is provided with all of our algorithms and 1D TEM stacked resistivity sections derived utilzing station by station or using a multi-station window. For assistance with any problems that you might have please contact support.

New Fortran Compiler
For many of our processing intensive algorithms, we utilize Fortran as this is still the fastest and most accurate language for massive computations. Intel having purchased copyright to the DEC Fortran compiler from Compaq (HP), began development of an improved compiler optimized for its chips eventually releasing a version in 2008 which provided capabilities to use multiple core processors as well as providing array processing capabilities. During the early years of the millennium, there were still many CPU’s being used but in the last 5 years, Intel has now dominated the market. AMD is another significant provider but its chips utilize the Intel architecture and thus the new compiler is compatible.

In the past year, we have been experimenting with the use of this new compiler and have been very pleased and surprised by the results. First, simply modifying the code to be compatible with the new compiler and re-compiling, we discovered huge unexpected improvements. First, and probably most important, massive computing on an Intel chip is now as stable as it has been historically on the AMD chips. Secondly, the floating point operations are more accurate than our older Microsoft FORTRAN compiler and then the most pleasing improvement, a general 5 times reduction in computation time! And this improvement is without the use of multi-core processing of any kind. The other aspect is the ability to implement use of the multi-core processors now available on virtually any computer. This capability now turns some tasks from being a day-long computation to only minutes.

Specific V9.0 Release Implementations
It will take some time to translate all of our algorithms into code that can be compiled with this new compiler but this will be an ongoing aspect of V9.0. However, for the release, we have implemented modifications to four applications. First, the 3D gravity inversion has been implemented for the new compiler but with only matrix operations using array processing capabilities. But, this has dramatically improved the speed and thus now allows very large data sets and very large inversion grids, producing inversions in reasonably short times. The 3D magnetics inversion, has been completely redeveloped to utilize the new compiler for array processing and multi-processor computations. The beauty of this new compiler, is that it will utilize an optimum amount of the system resources without threatening the stability of the operating system as with other multiprocessing compilers which also allows the user to intervene and do other tasks. Intel has integrated computation and the Windows environment in a superb manner. Finally, we have implemented several of the new compiler’s capabilities in our data interpolation algorithms. EMIGMA is quite unique in that it allows for rectangular grid cells, arbitrary grid angles and other aspects important for interpretation and resolution. These capabilities are particularly important for potential field data where the grids can be utilized for accurate Fourier processing as well as Euler depth estimation. Now, even the largest airborne survey can be gridded both accurately and in a time efficient manner.

Finally, we have implemented the new compiler, partially, for our freespace EM algorithms. These algorithms are for the inductive response of a thin conducting sheet. These algorithms are unlike other inductive plate algorithms in that they are not restricted to concentric current rings but allow a full expansion of induced currents in multiple geometries. This allows for accurate simulations of even long strike conductors but more generally for non-uniform excitation of the conductor which is most important for airborne systems which have large spatial gradients in the exciting fields. This type of excitation is not suitable for many freespace algorithms. Our algorithms are of two forms, one which is merely the freespace response and the other allows for the combination of an inductive response along with the response of a conducting host. While these algorithms do not allow for galvanic excitation (provided in another of our algorithms) it does include an important response even in resistive environments and that being the response of a conductive or weathered overburden. These improvements offer a 100 fold improvement in computation speeds.

Network Dongle
EMIGMA is license protected via a USB dongle. Previously, the dongle had to be connected to the computer upon which EMIGMA was being utilized. This was of significant inconvenience for institutions which had multiple users as the dongle had to be transferred from one user to another with the possibility that the dongle could be easily lost or stolen. Now, the network dongle may be installed on one secure system computer and utilized by users when the license is not being utilized by others. This type of license may be purchased for one or more simultaneous users. For information on how to convert your dongle to a network dongle please contact support.

Inversions
We are pleased to introduce a number of enhancements to our inversions, especially the Gravity, MT, CSAMT and FEM licenses.

3D Gravity Inversion
Firstly, we have added a constrained Trust region algorithm to replace the earlier slow method. This method not only results in a faster rate of convergence but also utilizes user-defined parameters. In fact, the inversion can now utilize user-specified density parameters and support the import and use of complex polyhedrons as starting models for such things as defining the topography surface or estimates of the basement topology. This is a radical departure from the standard approach of defining a layered-earth model or utilizing a previously-run forward model. Additionally, a number of changes were made to stabilize and speed up the inversion process. The inversion has also been upgraded to allow many more data points and cells in the inversion grid. We expect this inversion will handle your most difficult gravity inversion problem.

Shortly, likely in June, we will utilize a new compilation using the new Intel Fortran compiler which optimizes the inversion of all Intel and AMD processor architectures. This improves the speed to about 3 times of the new May release.

3D MT Inversion
- Improved capability to handle a large number of frequencies and cells and for larger data sets

3D CSAMT Inversion with 3D source
- Faster processing of the data set using a more robust method
- Ability to invert the amplitude of impedance as well as Inphase and Quadrature
- This is in addition to being able to use the measured fields if available.

1D FEM inversion
Supports multiple receiver configurations employed by DUALEM and PROMIS systems

Modeling
We continued to innovate and improve the accuracy of the modeling capabilities of our software over the past year. Some of the most important changes are highlighted below:

EM Simulation
We made some improvements to speed up the simulation procedure as it relates to the joining of the polyhedra (3D objects). The EM simulation procedure in EMIGMA is remarkably different from other applications in that it takes into account not only the interaction between the different structures of a model, but also the interaction between the polyhedra/prisms and the various layers (of the model). In the end, the algorithm computes a very accurate and realistic model based on the given information. Because this aspect of modeling is not handled appropriately in other modeling applications, this makes our software all the more unique and powerful.

We have implanted new capabilities for modeling VLF and VLF-R data. With the dramatic decrease in exploration dollars, many smaller exploration companies are returning to VLF for reconnaissance purposes.

Gravity and Magnetics 3D/2D modeling
Already our Potential fields modeling are both fast and accurate. However, we are presently testing new compilations of the algorithms using the new Intel compiler and this is resulting in improved speeds by up to 10 fold. These upgrades will be available in June.

Mapping
We have added several new features to enhance the mapping capabilities of our software.

Grid Presentation tool
Using Grid Presentation, the user is now able to print any scaled image to a number of large-size map formats, thereby eliminating the need to use highly-specialized and expensive software or printing facilities. The user can customize the map to include a legend, add a logo (or any raster image), create a text box and change the layout of the map prior to printing. Following formatting changes, the user can print the map to PDF by selecting the appropriate paper size including Architecture sizes (Arch A-E) and simply have the map printed professionally. Alternatively, the user can also print directly using any of the supported paper sizes, as needed.

Another unique feature is the ability to manage the Contour attributes. The user is not restricted to pre-defined contour levels, but can instead define the contour interval, draw labels and control the formatting and frequency of the labels—all from within this tool.

Additionally, this tool provides the user with many practical features for handling Transparency/Overlays. For instance, the user can work with up to 5 layers, which include an interpolated ‘Mesh’, Map (Georeferenced map can be loaded), Filled Contour, Contour Line as well as (Survey) Profiles. Using this feature, the user may change the order of the layers and adjust the transparency of each layer. The result can then be exported to a number of formats (raster or raster with Georeferenced formats) and printed, as needed.

Data Import and handling
- Added new FEM import for the GEM-2 system
- Added new FEM import for PROMIS and DualEM
- Improved error handling for MT data (tipper and impedance components)
- Various changes introduced to make the MT/Tipper data import more user-friendly
- Added VLF and VLF-R imports
- Upgrades to CSAMT imports for use with 3D source modelling and inversion to overcome the limitations of the far-field approximations
- New IP imports from QCTool

Processing
- Implemented a new 12th generation IGRF calculation for accurate processing of the magnetic data
- Better handling of DC magnetic derivatives and grid processing features
- Easy conversion of survey data between static and frequency domains as well as frequency and spectral domains
- Ability to select electrode coordinates and specify channels and separations when exporting IP/Resistivity data to XYZ format

GBDecomp
- Updated and improved user interface
- Enhanced support for handling MT data with multiple stations (in a .qct file)
- Enhanced import of decomposed data to EMIGMA for modeling and inversion

Plotting/Display
A number of improvements were made to the overall plotting and display capabilities with some notable exceptions listed below:

IP/Resistivity/MMR
- Ability to plot data as a function of separation
- Accurate calculation of apparent resistivity from a variety of conventional and unconventional survey configurations
- New display options to switch between ‘actual’ and ‘absolute’ data when calculating apparent resistivity
- Several improvements for displaying apparent resistivity using PseudoShow and Grid Presentation

MT/CSAMT
- Added a number of intuitive features for plotting impedance data
- Adept handling of 2D decomposition features for layered-earth models

Misc. improvements
- Better handling of static MMR surveys including Xhole surveys (with both E -dipole and H-dipole receivers)
- Improved forward simulation of DC magnetic and gravity data
- Utilization of gridded data for the Magnetic Vector Inversion (MVI) - Ability to export Euler solutions to .qct file
- Better interface support for the Remanent Magnetization parameter

Polyhedron generation tools
- Ability to generate topography (as a polyhedron file) by combining two .EGR grids (QCTool grids), one for the top of the structure and the other for the bottom.

With the introduction of new ground FEM systems, we have upgraded our tools for the newer systems particularly PROMIS, DualEM and GEM2. The PROMIS system is a radical improvement to the old MaxMin system, allowing for 3 component receiver data over multiple frequencies. The DualEM offers 2 receivers and the GEM2 offers multiple frequencies. Other new systems are in works.

Data imports and processing

We now offer data imports to QCTool for the PROMIS, DualEM and GEM2 systems. After you have processed your data in QCTool, we have simple imports for these systems into EMIGMA.

Quick Data Interpretation

Much ground FEM data is presented in units of apparent conductivity which is determined by a simple formula which is only appropriate for low frequency short TX-RX offsets. As such, we convert this data to proper normalized to free space units (e.g. percent, PPM or PPT). However, it is useful to obtain an apparent resistivity which is determined by inverting the Quadrature data – component by component and frequency by frequency – to the best fitting halfspace. This is appropriate for several data components including HCP, VCP, VCP broadside, and the so-called PERP data (vertical TX and inline HX). These functions have all been added or improved in EMIGMA. Also, these same components can be used individually if multiple frequency or together for single or multiple frequency for 1D inversion. We offer a range of 1D inversion with appropriate visualization for these systems.

3D Modeling

EMIGMA offers a range of 1D and 3D modeling capabilities for FEM systems. The model can be wide ranging offering resistivity, permeability and permittivity variations. It is quick and robust.

• 3D gravity inversion: added a new constrained trust region inversion technique
• 1D CSAMT inversion: multiple data joint inversion of apparent resistivity or electric or magnetic field data.
• New automated extended volume for 3D magnetics inversions
• 1D FEM: incorporated displacement currents for high frequency data Occam inversions. Replaced Marquardt line search technique with volume trust region technique.
• 1D FEM Apparent Resistivity Inversion: replaced old style golden search with a modern inversion approach producing more stable and reliable results
• 3D DC Resistivity Simulations: some major enhancements
• 3D Non-Linear ( full solution ) Forward Magnetic Solutions__: enhanced speed considerably by some software architecture enhancements
• Freespace Plate: Added crosshole computations
• MMR forward solution improvements
• Synthetic Surveys: for those of you who have utilized the feature in EMIGMA to build synthetic surveys, we have finally made the task much easier. There is now tool in the Configuration tool (Profiles) which allows you to set up a multi-line survey much quicker.
• Import Additions:
  • Multi-Frequency IP data (spectral IP)
  • Surface to borehole IP
  • New format for Zonge CSAMT with improvements
  • SMARTem import

We will note here again for emphasis that EMIGMA for CSAMT is very unique in that we utilize the actual source geometry and thus are not limited to assuming that the data is in the far-field. Please also note that even when in the far-field for a controlled source this presents a very different source to the plane wave geometry of MT/AMT which forms the basis of all MT/AMT interpretation software. Please contact us if you have interest in such CSAMT capabilities. For CSAMT, we offer both current and magnetic sources for standard CSAMT and the Stratagem.

Data imports and processing

As for other applications in EMIGMA, our focus has been to provide comprehensive input to our processing product – QCTool - in order to use the wide range of quality control and editing tools in this product. After processing in QCTool, it is a very simple matter to import your MT or CSAMT data to EMIGMA. We support general ASCII columnar, Excel .csv, .edi and manufacturer’s native formats. If you have a format that you would like supported, please contact us at support@petroseikon.com.

MT Data Presentation

We offer a comprehensive plotter to plot all elements of your MT data in various forms as well as profile plots and spectral plots (function of frequency or period). The Plotting software also allows you to calculate and plot various standard MT processes such as principal impedances, the 2D strike estimator, the skew and the impedances under rotation. Of course, tipper plotting is also provided. When gridding your data, there is a range of 2D and 3D display capabilities.

Quick Data Interpretation

EMIGMA offers 3 quick methods to interpret your data, Smooth Overparametrized 1D inversion, Under Parametrized 1D Inversion (the inversion process is not a Marquardt line search but a more robust volume technique) and the very traditional Bostick-Niblett transform. All of the results, may be viewed in 3D volumes, 2D resistivity sections, line plots or the actual numbers. Results are easily exported both in plane and section.

2D and 3D Modeling

EMIGMA has had very fast and accurate 3D modeling for MT/AMT for over 15 years, however there has been some notable improvements over the last year allowing for even more complex models. Your models may also be converted to a format for import to CAD software. For 2D modeling, it is simply a matter of defining a strike length for your structure and constant electrical properties along strike. Any strike length can be used as there are no limitations to strike length. Note that EMIGMA includes all the scattering processes including the sharp effects of charges at resistivity boundaries and proper field interactions between multiple anomalies.

3D/2D MT Inversion

EMIGMA has had 3D natural field inversion of a few years now for both impedances and tipper vectors. However, in this year, we have made some very important improvements in functionality, the stability and speed of the inversions and many improvements to the user interface. All elements of the impedance tensor may be used in the inversion process.

As standard 2D inversion imposes a very unrealizable boundary condition for the MT polarization, we should provide a more realistic 2D inversion wherein the inversion grid has a defined strike length with constant model parameters along strike. Inversion may be performed on either the Zparallel impedance or the Zperpendicular impedance or as we prefer on both impedances.

The inversions use our proven trust-region approach with the inversion of a scattering matrix utilizing very modern, fast tools for matrix inversion. There are virtually no limitations to the size of the inversion grid since if the matrix is too large then allocated virtual memory will be used. The inversion is fast!

Decomposition Software and Removal of Static Effects

We now provide with all MT licenses our Impedance Decomposition tools. If using 2D interpretation, you may analyse your data to determine the best 2D strike and produce the principal impedances formed by that strike angle. If the data is 3D, then one may use the 3D decomposition of Groom and Bailey to remove and correct for small-scale static effects.

The software provides import from QCTool format to the format required for the 2D and 3D decomposition and plotting tools to look at parameter results and the fit of the decomposition to the data. Once completed, the results are exported to .qct for import to EMIGMA.

Data imports and processing

• Range of native instrument formats – Zonge, GDD, Scintrex, IRIS
• Improved generic format imports – (Geosoft compatible)
• Enhanced data processing in QCTool and then easy import to EMIGMA
• QCTool is now a very useful tool for editing and processing your field data to clean up errors in the data, check repeats, plot data, etc.

Survey Configurations
EMIGMA supports a wide-range of configurations – Dipole-Dipole, Pole-Dipole, Pole-Pole, Gradient, Schlumberger, Wenner, Surface to Borehole, Borehole-to-Borehole, MMR, MIP

IP Data Presentation
EMIGMA is unique in that you can work with your time domain IP data either primary voltage normalized or simply as current normalized ( i.e. the entire survey is set to a constant voltage through the import and merging process). The former is quite conventional where the latter offers you a very different view of your data. In this case, data is present as on-time data ( your resistivity data) and off-time data with both in the same voltage units. In this way, you can examine your data as you would your TEM data. You will find this capability very useful in understanding your data. You may with a click of the mouse convert your data or your modeled data to the standard convention.

Data Display and Analyses and Correction
QCTool offers a very easy to use, inexpensive and comprehensive software package for basic data displays, analyses and corrections. Extremely light weight as regards system requirements and very convenient both in the field and the office.

EMIGMA provides a range of tools for data imaging including

• A very comprehensive data plotting tool allowing displays via profile, time window and separation. Multi-component and multi-line plotting, data vs model plotting and many other useful features.
• A multi-dimensional grid and display allowing to incorporate in one grid, all separations and all time windows or frequencies. High resolution grids and grids with varying grid points depending on centre point changes.
• 3D surface displays of data
• 3D pseudo-sections
• 3D volume displays of inversion grids and models
• 2D pseudo-sections and resistivity-depth sections

Forward Modeling (ie. Simulation of Model Responses)
EMIGMA offers comprehensive 3D and long-strike 2D for resistivity and time and frequency domain IP. Several algorithms are provided, some for quick approximate solutions and others somewhat longer computations for a complete and fully accurate solution. In the complete solution, no shortcuts or approximations are made. The full effect of the charges, interactions between targets, effects of the current and voltage wires, etc. are accounted for. We have done considerable work for this release to improve all aspects of our solutions. But, there are some new additions
- Surface to Borehole and Borehole to Borehole both for voltage receivers and for magnetic receivers (MMR and MIP). This necessitated some additions to our tomography tools.

3D Resistivity Inversion
EMIGMA has had 3D resistivity inversion of a few years now. But, in the last year, we have had the opportunity to use it ourselves for contract work. As a result of this work, we have made many improvements to the inversion tools and we believe you will find it more than a little interesting to utilize our inversion and compare to other inversion code that you might have. For example, try some accurate forward models and try your other inversion out on the results. You may be surprised.

2D Resistivity Inversion
The 3D resistivity inversion tools are available for 2D inversion for a single line. The software recognized automatically that there is only 1 line and builds an appropriate grid. Note: There is no mathematical foundation for a traditional 2D inversion but there is no reason one cannot have a single constant grid cell along strike. We automatically select an appropriate strike length for these cells but you may modify this length as you wish. In this process, an output inversion section file is produced for viewing in our PEXSHOW tool or exporting to other software.

1D Resistivity Inversion
EMIGMA offers both over-parametrized inversions (so called Occam) and an under -parametrized global search method. These are useful with your data even if not in a 1D environment as they give useful structural information as well as depth of investigation.

3D IP Inversion
We are working on this and hope to have something for you to try later in the year.

Data Import into EMIGMA

Inversion

• 3D Resistivity Inversion tool has been enhanced to allow superposition LN forward technique. This enables current interaction between cells and to our knowledge is the first Resistivity inversion tool to allow such necessary current interactions.
• Improved handling of exceptions in the 3D Resistivity inversion tool
• 3D Resistivity Inversion has been overhauled to allow enhanced forward modules for faster computations in the simulation portion of the inversion process.
• Marquardt style underparametrized inversion method added to 1D MT/AMT inversion tool in addition to our original over-parameterized Occam style inversion.
• Improved apparent resistivity calculation for 1D resistivity and 1D CSAMT tools
• 1D CSAMT inversion tool has far field inversion technique for impedance data. Thus, adding the traditional approach for comparison.
• Several new features added to 1D CSAMT inversion which includes inversion for E,H or Z including the generation of a log file for recall of previous inversion settings
• 3D MT/AMT inversion has been added including Tipper Vector inversion
• Born or Superposition interactions allowed in MT/AMT/Tipper inversions
• Addition of use of log file for MT/AMT/Tipper inversion
• Graphic tools for setting inversion grid for MT/AMT/Tipper inversion
• Improved Marquardt and Occam 1D inversions for DC resistivity for speed and accuracy
• Improved user-interface for 1D resistivity inversion
• Improved exception handling for 1D MT/AMT inversion
• Improved accuracy and speed of forward simulations during 3D Gravity inversion
• New constrained trust-region inversions for DC Magnetics
• Added data weighting capabilities in 1D TEM inversions for ground and airborne surveys.

Forward Simulation

• Improved accuracy for extended ground sources including CSAMT, MMR and gradient IP.
• Improved borehole simulation accuracy to account for variations in borehole geometry
• Various improvements for borehole methods including EM, Magnetics and Gravity
• Internal current sampling points in LN (Prisms and Polyhedra) increased to 8000 from 3000.
• Extensive re-working of Greens functions calculations improving simulation accuracy dramatically for difficult models. For all IP and EM techniques
• Numerous small improvements for stability in EM calculations
• Improved simulation speeds for 3D Gravity and Magnetics forward simulation
• Major reworking for 3D DC Resistivity and MMR simulations including upgrades for very large internal field, equivalent source sampling
• General improvements to cancel simulations and handle processing exceptions

EMIGMA Plotter

• The Plotter in EMIGMA has always been a very useful and efficient tool for data analyses
• As we do every year, we spend extensive efforts on improving functionality and stability to make it even more useful and efficient
• Component selection can be applied to all plotted channels at once allowing much more rapid comparison between data and multiple models
• Improved error bar display in decay mode
• More plot settings can be saved for plot recall
• Improved Xhole data display functions

Visualization in EMIGMA

• A variety of improvements to visualization tools
• Improved import/export of structures including 3D AutoCAD and Surpac formats
• Improved visualization of 3D field vectors
• Enhanced capabilities for Xhole surveys
• Improved display settings for TX and RX displays
• Improved data display
• Improved user interfaces
• Improved ability to check and handle exceptions
• Improved section cutting in display of 3D inversions and data
• Improved functionality in 2D section displays
• Improved display functionality for 2D grids for MT/AMT data

Profile Modifier Tool ( analyze and edit survey geometry)

• This is a rather new tool in EMIGMA and was initially designed for editing and cleaning large airborne surveys.
• Over the last years, it’s functionality has constantly increased as it has become one of the primary tool in the EMIGMA application
• Now we can display your transmitter(s), determine the exact location of the source vertices and receiver locations. Identify and edit data lines and labels. Underlay maps and export maps to a variety of mapping software products including geotiffs and 2D .dxf.
• One useful feature in this year’s additions is the ability to project your anomalies onto the surface in order to analyse their location with respect to transmitters and receivers as well as to produce maps for reports.

Other new features in EMIGMA

• Mdb database files can be associated with EMIGMA so that the database will be automatically opened into EMIGMA when double-clicked
• Tipper rotation has been added to the toolbox, plotter and visualizer
• Editor for axis and transmitter display parameters in 3d Visualizer
• Transmitter information is displayed on status bar in survey editor and grid contour tools
• Time window shifting and multiplying
• Data is not lost when Rx settings are modified
• An external station location file can be used to convert local grid coordinates to UTM
• Improved data processing tools and data reduction calculations

CSAMT, MT/AMT, ZTEM Tools

• Over the last few years, we have had increasing demands to upgrade our tools for these surveys and have also been contracted extensively for consulting purposes for these types of surveys thus requiring enhancements for these purposes
• As a result, we have had to update all the tools for these surveys starting from data imports onto processing, data display and analyses and finally to modeling and inversion.
• You will now find EMIGMA a much friendlier and comprehensive tool for these surveys

QCTOOL

We include our developments in QCTool since this product has now become a very useful appendage for working with certain data types and EMIGMA. QCTool allows for easy import, QC/QA, editing, processing and data merging. Import from QCTool to EMIGMA is extremely user-friendly.

New Import Facilities

1D Inversion: We have utilized Occam type inversions to date, but as a process of upgrading our MT tools, we have added a parameter constrained “Marquardt” style inversion. These inversion tools are quite different from the original Marquardt inversion techniques yet similar. It is an under-parametrized inversion approach and uses analytic gradients and numeric curvature terms but the actual minimization approach is much closer to our other documented inversions. (See downloads page).

Display Capabilities: Some significant work has been done on plotting, gridding and visualization displays for natural field data.

3D Tipper Inversion: A 3D tipper inversion in available but is not part of the standard license. Please contact sales if you are interested in such algorithms.

3D Impedance Inversion: We are in the last stages of testing and hope to have something available for September. This will be part of the standard MT license and will be free as an upgrade to all clients having licenses under maintenance.

CSAMT Developments

For many years, EMIGMA has contained 3D CSAMT modeling. However, it was quite distinct from standard CSAMT modeling in that the actual geometry of the transmitting wire was used including not only the injected currents but the currents induced in the ground due to the magnetic fields emanating from the wire.

A few years ago, with UN support, we upgraded our CSAMT tools to import Zonge data including both impedances and the synchronized measured fields (ie. Voltage and Magnetic fields). At this time, we also added constrained 1D inversion using the full source effects. These developments combined to allow the use of data not only in the far field but also in the near field thus allowing the use of all measured frequencies.

Recently, we have upgraded our CSAMT tools again and are in the middle of more extensive developments. First, we have upgraded the import tools through the .qct format thus essentially allowing any data that can be formatted to a spreadsheet or .xyz format to be imported. Also, as part of new developments to more closely support all Phoenix instruments, we have developed imports to EMIGMA for their .avg format which includes impedances and fields.

Generally, we upgraded our display and survey design tools for CSAMT so as to move closer to having the combination of EMIGMA and QCTool be a comprehensive tool for survey design, QC/QA, processing and interpretation for CSAMT. This is motivated by what we see as a strong growth in the wish to use such data and by the limitations of being forced to interpret such data as MT data but also due to our involvement as consultants in such projects.

We have reworked our CSAMT 1D inversions to be more rugged, accurate and fast. 3D CSAMT inversion is in development and likely to be released in the fall of 2012.

Enhanced 3D Inversion: There have been extensive improvements to the 3D Gravity Inversion algorithms allowing for much larger problems to be solved. In addition, the new algorithms are about 10 times faster than the previous algorithms. In addition, the 3D Gravity inversion interface has been extensively modified and improved so that its appearance and functions are more consistent with that of the other inversion tools. Some improvements have been made to the Magnetic Inversion to bring both the interface and algorithms inline with the capabilities of the Gravity inversion. Similar changes have been made to the 3D Resistivity Inversion.

Chinese language documentation: We are currently translating some of our manuals, tutorials and videos from English to Chinese. Look on the Chinese page of our website for the materials that are available.

Importing Data
• FEM Dipole-Dipole data can now be imported from QCTool files. As well, extensive improvements have been made to import the GTK fixed wing AEM data.
• MT data stored in Zonge’s .avg file format can now be imported
• Moving loop TEM data in a Crone format can now be imported.

Xhole Modeling Tools: A number of updates have been made to the capabilities in EMIGMA for modeling different types of transmitters and receivers for Xhole applications.

GeoElectric CrossSections Display: Significant improvements have been made to our display capabilities for sections produced by 1D inversion applications within EMIGMA.

CDI processing can be interrupted before completion so that the processing can be resumed at a later time. Improvements have been made to the accuracy and stability for apparent resistivity and apparent depth for FEM data.

Exporting inversion models: Two formats are now offered for exporting 3D inversion models to QCTool and thus to ASCII.

New QCTool features
• More advanced tools for UTM coordinate and longitude/latitude conversion with many new datums and projections added.
• KML file format used with Google Earth and Google Maps can be both be imported and exported from QCTool
• AutoCAD DXF can also be imported for use in QCTool

Other new features include being able to copy a profile from another survey and new capabilities for manipulating polyhedra within EMIGMA’s Visualization environment. Many other small improvements have been made to the Visualization tools.

Upcoming Features
3D Inversion for MT and CSAMT is coming very soon: The CSAMT inversion will utilize the 3D aspects of the source and thus there is no requirement to be in the far-field. Also, the Voltage measurement and the Magnetic measurement in the CSAMT inversion can be used individually, together as a joint inversion or as an impedance ratio. Obviously, E and H in a CSAMT survey are sensitive to different 3D features.

• Recompiled and optimized for use with Windows Vista and Windows 7
• Contains all new features and fixes from update patches created since the release of version 2.2
• Support for Scintrex ENVI/ENVI PRO data import format
• Add new line functionality
• Many memory allocation errors are fixed

Users with a current license may run the update utility in order to use this new product. Others may go to the download page for a 30 day trial.

Improvements to the use of Crone data: We have released a range of new as well as improved functionality for working with Crone borehole and ground data including TEM, DC Magnetics and MMR. For example, we import the 3-component DC magnetic data from the horizontal components’ file and de-rotate the data and import so that the user may directly model this data. We also now work directly with the .raw files as well as .tem files. The .raw files allow the user to import repeats for examination of noise levels. Later, the repeats may be stacked in EMIGMA for interpretation purposes. For the borehole data, the .raw files allows the de-rotation of the data within EMIGMA. This is useful when there are de-rotations issues with the Crone implementation and we may directly examine the issues within EMIGMA and provide quick fixes if required.

Modeling Crone TEM data: We have been working extensively with Crone surface and borehole TEM data carrying out numerous calibration tests and believe that we are able to more correctly simulate their data than has previously been available both within EMIGMA as well as other software. Working closely with our client with underground intercept results and drill logs, we have been able to determine how other common software mis-represents Crone data in their models thus leading to grossly incorrect interpretations. You may want to contact us on these issues at support.

TEM Inversion Enhancements: Previously, we had released versions of our inversion software which allowed the use of multiple data points to determine an inversion model. These tools allowed the user to move along flight lines with a moving selectable window which provides much enhanced and more reliable inversion results. But, for fixed loop results, the user could only gain 1 inversion model from an inversion. Now, the user may select a moving window and move along profile lines inverting for 1 model per window position. This brings to full play our knowledge that multiple stations do not suffer a lack of uniqueness to the same extent as single stations models.

Magnetic Inversions: While we have previously released 3D magnetic inversions which allow the use of both airborne and ground data to derive a model significantly reducing the uncertainty in the inversion especially when utilizing derivatives ( either measured or processed), we are now experimenting with the joint use of airborne, ground and borehole data for better resolution at depth. This capability adds to our ability to constrain with core results. The results appear very successful and should be available for our client’s use in the near future.

MT/ZTEM and CSAMT Inversions We are well on our way in our progress towards 3D inversion of MT and ZTEM data as well as 3D inversion of CSAMT utilizing the 3D source characteristics. Look for availability of the first of these algorithms in early Fall, 2011.

The MMR license includes both ground and surface-to-borehole MMR capability as well as underground or Xhole DC resistivity capability. In addition, this license includes borehole DC magnetic modeling.

New Magnetic Inversion Algorithms and Tools
Partially because of our own needs for improved magnetic inversions for our extensive consulting work in the gold exploration industry, we have done a complete re-work of the inversion tools including many new improvements.

Last year, we released 2 new fast matrix inversions tools to allow both faster and larger inversion processes. Last fall the inversion algorithms were reworked to be faster, more stable and allow larger inversion tasks. But even more importantly they were upgraded to allow joint inversion of multiple data sets. Thus, the user can now jointly invert, for example, both ground and airborne data with or without magnetic gradients either measured or derived from FFT grids. Additionally, we have entirely re-worked the interface to allow an easier grid definition with visual aids. In addition, we have added to the ability to use both linear and exponential vertical grid definition, the ability to mix different linear depth thicknesses for different vertical depths of the inversion grids. Thus, one can define thin shallow grid definition with intermediate thicknesses at intermediate depths and thicker thicknesses at depth.

Additionally to these improvements, we have added the ability to constrain the model with borehole susceptibility information as well as ground samples of susceptibility. Also, added is the ability to process the inversion grids to remove cells of defined sensitivity. Thus, one can remove weak susceptibility cells to focus on the main structures, view the refined grid and re-compute the response of the refined grid.

The result is a fast, stable, accurate and flexible inversion product which is very suited to enhanced resolution of the derived structures.

Static Borehole Data and Borehole Geometry Imports

For a longtime, we have been able to model borehole total field magnetic and vector data as well as gravity data. Now, you may import the data for comparison to models and utilize in your gravity and magnetic inversions.

In addition, we have augmented our tools for importing the borehole geometries which also allows you to import other borehole data. This allows you to view the borehole geometries in conjunction with your models as well as with our new tools for importing mine workings into your visual displays.

New Polyhedral Structure Builders

We have added three new tools for importing structure into a complex polyhedral volume. First, we have augmented and upgraded our tools for importing GEMCOM .tri files allowing one to import geological models from several applications most notably from GEMCOM and GoCad. Secondly, we have added the ability to import three dimensional volumes from a QCTool grid. This for example, allows one to build a topography model in QCTool and then export to EMIGMA as a 3D volume. But, generally it allows one to import a 3D surface into EMIGMA and give it an arbitrary thickness. Finally, one is able to import a polyhedral model based upon an ASCII 2D geometry and give the structure a radius. This is most useful in importing such things as mine workings into EMIGMA to view in combination with models and borehole geometries.

Additionally, we have moved these tools into a direct capability from the main EMIGMA database interface.

Crone Borehole TEM and Magnetic Data imports: Crone TEM data offers some very large advantages to other impulse data in that it provides accurate and reliable measurements during the ramp (on-time) with the advantages of impulse measurements as well as offering 3-component magnetic data.

We have augmented our imports and functionality in several ways. First, the user may import the raw (un-averaged TEM) data and perform the borehole rotations either from Crone data information or other borehole geometry information. Secondly, one can import the borehole magnetic data from the raw files and de-rotate without the need for Crone processed magnetic files.

We have been using Crone data extensively in our own consulting services and find these tools extremely convenient and effective.

Shortly, the user will be able to import the Crone MMR data and use it with our new MMR modeling and display tools to be available by summer 2011. If you have need to model this type of MMR data please contact us at services@petroseikon.com

Data Processing

We are always augmenting our processing tools to meet the need for enhanced data processing. Recently, we have added 3 new tools

Convert units: This allows the user to convert units of both measured and simulated data to other data units and then continue with processing, modeling or inversion.

Data Outlier Removal: a convenient tool for removing outliers in your data. User selectable ranges are allowed.

Vector Rotations: Often it is necessary to rotate your vector data. This tool allows an accurate, flexible and user-friendly way to perform these operations.

PROMIS FEM imports and tools: The new PROMIS FEM equipment is easy to use and accurate piece of equipment allowing one to rapidly collect accurate multi-frequency and multi-separation FEM data to replace the aging Max-Min instrument. Our own tests of the instrument show it to be a reliable and efficient instrument. As such, we have improved our tools to import and utilize the data both for modeling and inversion.

Vector Magnetic Data Imports, Modeling and Inversions: We have extended our magnetic imports to allow import of vector magnetic data for either ground, airborne or borehole data. The imported data then allows easy modeling and inversion setups.

Gradient Gravity Data Imports, Modeling and Inversions: We have improved our gravity imports to allow import of any or all of the tensor components and then the data can be used directly in our modeling and inversion tools.

Upgrades to Resistivity/IP Imports: Upgrades have been made to import such data in either the generic Geosoft formats or ELREC 6 formats or Zonge GDP_32 formats. This allows quick access to our display tools whether as plots, sections or 3D visualization as well as for use with our 2D/3D IP/Resistivity modeling or 1D or 3D Resistivity inversions.

Survey Editor Upgrades: Our survey editor tool is very useful for reviewing and editing your surveys. New tools allow displays of sources as well as the co-ordinates of the vertices of your source.

Mapping Upgrades: New tools allow the integration of maps particularly with transparencies and then outputting to MapInfo or Arc Map Geotiff formats.

We trust you will enjoy and appreciate these new features in our sub-release EMIGMA V8.5.5.

• Magnetic Data Import: extension for multi-sensors
• UTEM3: Point-Normalization option
• Airborne TEM: Upgrades to handle HeliTEM including imports and rotation of receiver unit
• Airborne TEM: Upgrades to allow normalization by current channel
• Mapping overlays/underlays and transparency upgrades for Grid Presentation and Profile Modifier tools
• CSAMT: New CSAMT 1D inversion with 3D source, inversion for impedance, E-field or H-field as well as inversion for multiple stations
• SMARTTEM data import in Amira format
• 3D Magnetics and Gravity inversions: Extensive enhancements to improve stability, speed, size of inversion grid and size of data set
• 3D Resistivity Inversion: A new addition to the 3D inversions that EMIGMA offers
• Plotter: Addition of error bars if error data exists
• Plotter: Improvements to MT display allowing direct plotting of 1D and 2D estimators from the loaded impedances. This includes Strike Angle, Skew Angle, Principal Impedances, 1D Impedance average and determinant estimators
• Visualizer: Now supports visualization of huge inversion grids
• Apparent Resistivity Calculation for TEM: Improvements to invert each time channel for halfspace apparent resistivity
• Aeromagnetic Compensation: This functionality is no longer supported in V8.5, however it is still supported in QCTool.
• Inversion Model Export: 1D and 3D inversion results can be exported to a QCTool file
• Database Export: Added option to select a group of data sets that can be compressed to a single file

Zonge Data Imports in native format: EMIGMA has been augmented to allow direct import of the Zonge .avg format from the GDP32 for CSAMT, Resistivity/IP (frequency domain and time domain) as well as TEM data. The CSAMT import allows import of Efields and Hfields as well as the impedance data.

CSAMT Inversions: We have added the inversion of CSAMT data to our suite of one-dimensional inversions but with some twists. First, the true 3D source is utilized allowing the effective use of non-farfield data and secondly, the user may invert impedances, Efields or Hfields. Thus, in this manner, one may actually effectively utilize your CSAMT data without regard to farfield assumptions which almost never occur over the entire range of utilized frequencies and the separation of the e- and h-measurements.

VTEM waveform: We have augmented EMIGMA to allow a much more accurate representation of the VTEM waveform. This can be utilized for much more accurate inversions as well as 3D simulations. Both the new waveform and the traditional waveform are now offered.

Moving System TEM inversions: Our extremely effective TEM inversions have been further extended to allow horizontally constrained inversions. In this implementation of horizontally constrained TEM inversions, the user is ask to select the length of a moving window of stations along a line or flight as well as the weights assigned to each location in the moving window. The inversion then moves along the line inverting jointly all the stations with weights to produce a model that fits all the stations within the windows, stores that model and moves the window along. The windows may be overlapping or disjoint.

Revised Exports: There is an ever-increasing demand to export EMIGMA results to other applications for such things as our processed data, grids, inversions and model results. We augmented most aspects of these export capabilities.

Resistivity Inversion: In the fall, we augmented our 1D resistivity inversion significantly including inversions for gradient data. Now, we are hard at work on our first 3D resistivity inversion application. We are hoping to see this released before the end of February 2010. This inversion will form the basis for other 3D inversions of galvanic applications such as CSAMT, MT and ZTEM data where the focus will be on inverted only galvanic and magnetostatic scattering effects.

Feel free to contact us for further details on any of the above items.

• Freespace EikPlate Algorithm: We are pleased to announce the release of a new 3D algorithm which we call Freespace EikPlate. The solution is only for inductive sources and magnetic receivers providing both dB/dt and B(t). Our solutions are based upon the doctoral thesis of Peter Annan and expands upon the older algorithm called UTPLATE which was used for many years in the 1980’s and 1990’s. It is a very fast algorithm but provides a more complete inductive solution than other ring current solutions which require relatively square plates and uniform excitation. At present, the solution is only for 3D inductive sources but we will later be extending for plane wave sources such as in MT and AFMAP/ZTEM.

• Import from QCTool, gdb to QCTool: We have been augmenting more and more of our data import tools to read QCTool files. This allows for user pre-processing of data as well as more stable and rapid importing of large data files. To this end, we have added the ability to directly import Geosoft .gdb files into QCTool.

• MT imports: We have provided significant expansion of the MT data and Induction vector data that can be imported into EMIGMA through the QCTool format. This allows very arbitrary formats to be first imported into QCTool, re-organized and then imported into EMIGMA.

• GDP32 imports: We are rapidly expanding our import capabilities for the Zonge GDP32 system. At present, we have added CSAMT and TEM imports through the older .avg format and will be shortly releasing the same capabilities for the newer .avg format. Later in the summer and early fall, we will be releasing import capabilities for IP that support both old and new .avg formats. Importing of Resistivity, frequency domain IP and time domain IP data will be available as well.

• Phoenix data imports: Users may now import Phoenix TEM data through the .usf file format as well as the CSAMT data via QCTool.

• Topography imports and simulation: We have simplified the steps needed to import XYZ topography data for modeling purposes. Simulation of the topographic effects particularly for potential field has been made easier as well. In addition, we have provided more extensive topography import capability through the use of a QCTool grid file. The user simply needs to import the topographic information to QCTool, grid as desired and then import the resulting grid (.egr) file into EMIGMA to reproduce the topography. The topography may then be subdivided if desired for different material properties.

• Magnetic effects in MT, Induction vectors and ZTEM/AFMAG: Due to the nature of the source, magnetic structures can be very important in natural field responses particularly for induction vectors (Tipper responses) for both ground and airborne data. We have augmented our simulation of plane wave sources to include magnetostatic and current channeling effects on the fields, particularly the magnetic fields.

• ZTEM/AFMAG: EMIGMA is now capable of importing, analyzing and simulating these systems. We have not yet released the tools but these capabilities are now available through our consulting services. Once we are satisfied with the stability of our tools and its representation with field data as represented by the manufacturer, these tools will be available.

• Polyhedral simulation capabilities: We have recently completed a large revamp of these capabilities and performed extensive testing. These upgrades are available through the Update functionality in EMIGMA.

• Terrain in Gravity and Magnetics: The terrain or topographic effects in Gravity and Magnetics are of continuing importance to our developments. Several new capabilities have been made available including: Improved terrain corrections in QCTool, Improved terrain modeling in EMIGMA and the inclusion of terrain in our 3D gravity and magnetics inversion.

Feel free to contact us for further details on any of the above items.

EMIGMA has offered a range of capabilities for tdem inversion including:

• In-loop and out-of-loop configurations
• Transmitter and receiver on different elevations
• Vertical and horizontal receiver orientations
• Occam overparametrized and Marquardt underparametrized models
• Full parameter constraints including selection of parameters for inversion
• Multi-layer starting models
• Rapid approximate (theoretical) current waveforms and true system waveforms
• Incorporation of system filters
• Storage of synthetic data from each location
• User control of time windows for inversion

However, we have expanded the functionality to now allow more flexibility for production including:

• Recovery of inversion settings from a log file
• Recovery of inversion processing from either a user initiated stop or a crash. Inversions processed prior to a user initiated stop are saved as synthetic model data so the user may later start up the inversion from the last processed position. Inversions and synthetic data are saved automatically every 100 locations so if there is a crash, you may start from the previous automatic save.
• The use of multiple starting models in any inversion processing procedure
• The use of the prior data point inverse model as the starting model for the next data point giving the user a style of lateral constraint
• Export of inversion models to formats suitable for import to 3D visualization applications and other mapping software

New:

On July 2, 2009, a new version was released allowing the use of multiple datapoints and/or multiple components. This capability is based on several obvious physical reasons but also on experience of many inversions calibrated to known structure. Among these are:

• Multi-component inversion for the same data location provides increased signal to noise aspects in the inversions but also allows more detailed resolution in the underparametrized model.
• In-loop data provides more accurate shallow resolution than out-of-loop data while the reverse is true for deeper structure. Thus combining in-loop and out-of-loop data provides significant overall shallow and deep structural resolution.
• If the earth is approximately 1D then a combined inversion of multiple data points provides the overall best structural definition. This is particularly useful when needing to do 3D modeling in a non-resistive environment where the determination first of the overall background resistivity versus depth is first required. This is also particularly important when inverting for long offset data where the receivers are far from the centre of the loop thus providing very accurate depth/resistivity inversions. As an example, you may download recent papers from our Downloads page.

We are working on new inversion capabilities for moving TEM configurations where multiple data stations may be used. The user will be allowed to define the width of the data station window and the weighting of the stations in the inversion. This will allow a smooth laterally inline constraint on the inversions.

Note: You will need a player which can play the avi format to view this video (e.g. Windows Media Player, VLC Media Player)

Download the EMIGMA video

Interested users should note that these capabilites are add-on capablilites to several of our products. Pricing for these add-ons are not included in our prices. Interested parties should request a quote or send an email to us regarding pricing.

Note: This import functionality will allow the import of Phoenix Instruments TEM data using the .usf format with slight modifications.

New features:

• Full Vista compatibility: Many hours have been spent to ensure that this version is fully compatible with Windows Vista and EMIGMA's compatibility extends to Vista's 64 bit edition. While EMIGMA, being a 32 bit based software package, will not utilize the full capability of the 64bit chipset and CPU, its design will enable some utilization of the 64bit capability. Many applications in EMIGMA run on their own thread and thus it is possible to make good use of a multiple core chip if you have such hardware installed.

• Online updates: EMIGMA's update capability, which allows you to download and install updates for the software has been improved. Clients in certain geographic areas, such as China, who have been unable to use this capability before can now take advantage of this feature.

• Contouring: The 3D visualizing contour tool has been completely redesigned to be much more robust and effective. Contours can now be integrated with a 3D surface and the interface has been simplified for ease of use. This tool allows for 3D volume rendering of your magnetic, gravity and EM inversions.

• FEM 1D Inversion: The inversion algorithm has been altered to recognize additional relevant factors such as displacement currents resulting in a more accurate inversion. A new constrained Marquardt style inversion has been added to allow you to use a starting model and parameter constraints. These upgrades for high frequency effects have been added to the apparent resistivity and apparent depth calculations.

• TEM 1D Inversion: Joint inversion of a customizable combination of components and separations for both Occam and Marquardt inversion types has been added. Incorporating more varied data into the process will provide better signal-to-noise ratios within the inversion. Being able to carefully select data that contain information about different geological structures may enhance the resolution of the inverted models and result in more meaningful models.

• Upgrades have also been added for the inloop approximate forward OCCAM inversion.

• The TEM Inversion is a full, correct forward modeled based inversion utilizing full parameterization constraints. It also utilizes a type of locally constrained inversion and is developed for production. Thus, inversions are stored after every 500 points and can be stopped and resumed at any time. Multiple starting models and constraints may also be defined for any inversion run.

• MT/CSAMT/VLFR Import: EMIGMA has been upgraded for import of table formats for MT and there is an entirely new import added which allows for you to import MT/CSAMT and VLFR data into EMIGMA from QCTool. Organization of ASCII files in QCTool is simple and thus any ASCII file can be reorganized in QCTool for import of these data.

• Airborne TEM imports: Airborne TEM imports have been entirely re-done with a new easier and more intuitive interface. For those of you working with large datasets, we have added the ability to import from QCTool.

• QCTool imports: We are moving more and more towards importing from QCTool. With its low price (and 30-day free use), it is possible to have your contractor deliver your data, import into QCTool to reorganize, edit and process, followed by interpretation in EMIGMA. Also, it is easy to transfer from a .gdb file into QCTool and vice-versa. Remember that you can process and reduce all of your magnetic, gravity and EM data in QCTool and if you are using the the IP12 series or lower of IP instruments, you can use QCTool for initial processing prior to import into EMIGMA.

• FASTTEM: EMIGMA has been upgraded to allow import and use of the FASTTEM system. TerraTEM data may be imported through the AMIRA format but a native TerraTEM import is coming in the next few weeks.

• MTEM: MTEM capability has been added. However, licensing is controlled by the company who paid for this development, so you will have to contact us if you are interested.

• Bug fixes and minor enhancements: Moving to 8.1 allowed us the opportunity to redesign some overall enhancement to functionality. In the interim, while enabling Vista compatibility, we were able to clean up a number of bugs and irregularities. Several new enhancements have been made. For example, you may pin the main page for ease of use when operating dual monitors and there is very nice right mouse click toggle from profile to decay in the plotter.

EMIGMA has offered significant capabilities for its inversion for sometime including

• Inloop and out-of-loop configurations
• Transmitter and receiver on different elevations
• Vertical and horizontal receiver orientations
• Occam overparametrized and Marquardt underparametrized models
• Full parameter constraints including selection of parameters for inversion
• Multi-layer starting models
• Rapid approximate (theoretical) current waveforms and true system waveforms
• Incorporation of system filters
• Storage of synthetic data from each inversion model
• User control of time windows for inversion

However, we have expanded the functionality to now allow more flexibility for production including

• Recovery of inversion settings from a log file
• Recovery of inversion processing from either a user initiated stop or a crash. This is achieved by saving the synthetic model data from the completed inversions at regular intervals so the user may start up the inversion from the position stopped
• The use of multiple starting models in any inversion processing procedure
• The use of the prior datapoint inverse model as the starting model for the next datapoint
• Export of inversion models to formats suitable for import to 3D visualization applications and other mapping software

Contact sales for information on how to purchase Emigma and start making use of these exciting new features.

Through our associations with consultants, instrument manufacturers and survey companies, we can recommend, supervise and quality control your survey requirements. With our years of experience in data interpretation combined with our understanding of the measuring equipment together and our mathematical expertise, we are able to provide a unique insight and understanding of your data. We can perform the processing of your data with a number of the industry's most exceptional software packages. Consequently, we are able to produce accurate inversions and 3D models to help you meet your exploration objectives. As a team, we are especially adept and quick at developing software which require special mathematical operations. However, as we have skills in visualization and database development, we also provide clients with solutions for these types of requirements. Geophysical data interpretation training is also provided.

Visit the services section of our website for more details on all that we offer.

Included among the new features of this version is its support for Windows Vista. Internet capabilities have also been added in the form of the ability to register your license online as well as the ability to obtain the latest enhancements to QCTool through an internet update tool. Another addition is the convenient function of being able to merge and separate subsets of data. The spreadsheet feature can now insert rows and has improved printing capabilities. The user interface of PEGeoMap, our GIS mapping utility, has been entirely redesigned and is able to read and write to several file formats.

It has been five years since PetRos EiKon first released Version 7.5 of its interpretation software package. The product is being received internationally with increasing popularity for its integration of software tools for non-seismic geophysical data. Initially released as EMIGMA V7.7 in May of 2004 and now (May/2006) in its third major release, EMIGMA V7.8, has an impressive array of new functions as well as improvements to almost all the older capabilities. In addition, many new features are in development to be released as upgrades later in 2006.

The new version continues to strengthen EMIGMA's historical focus of data simulation from 3D models:

• our first 3D gravity modeling algorithms
• 3D gravity inversion algorithms
• gravity and magnetics gradient modelling
• increased capabilities for magnetics including the ability to use gradients either measure or processed in the inversion tools modelling
• a new more accurate and faster 3D resistivity modelling algorithm
• a new release of layered inversion for resistivity including both Occam and Marquardt types inversions
• improvements to its electromagnetic modeling and inversion algorithms
• enhanced features to the frequency domain transform to handle several new TEM systems
• upgrades to our CDI tools for FEM and TEM
• many upgrades to our TEM inversions for both ground and airborne systems
• extended batch mode simulation
• greens' functions interpolation for faster multiple models
• model suite generation and automatic "best model" analyzer
• new helicopter TEM waveforms - AeroTem and VTEM
• inversion for magnetization vectors
• new Extended Euler solutions for both gravity and magnetics

The research team continues to add and improve functionality for inversion:

• 1D TDEM inversion for for both in-loop and out-of-loop configurations, including airborne systems (now available with either Occam or Marquardt techniques)
• Conductivity Depth Imaging improvements for ground and airborne TEM data
• enhanced 1D inversion capabilities for Resistivity (now available)
• new tools for Titan24 modeling
• extended and improved the 3D magnetics inversion capabilities
• 3D Euler Deconvolutions with Rodin Post-Processing including use of gradients and vector components (now available)with either grid or profile data

Of course, we are always working towards including new imaging and processing algorithms:

• V7.8 now has 3D Euler depth estimation for both magnetics and gravity data
• New visualization of Euler solutions, Rodin and Cluster post-processing of Euler solutions as well as vector magnetization displays
• 3D magnetic inversion utilizing total field and gradients
• 3D gravity inversion is now available (inversions for airborne gradiometry available on request)
• borehole gravity modelling
• 3D resistivity inversion available on request

But the vast majority of V7.8's increased functionality is directed towards providing the user with data processing, filtering and mapping functions. For example, this version provides:

• an array of FFT tools for both gravity and magnetic data
• several new reduction-to-the pole algorithms
• wavelength filters plus upward/downward continuation.
• FFT tools may be performed on both measured and simulated data for evaluation of user processing
• digital and spatial data filtering techniques allowing user-selectable filter sizes for both 1D and 2D filters
• many new mapping capabilities
• new gridding algorithms and grid analyses tools.
• a wide selection of datums for UTM and Lambert projections as well as projections for polar latitudes.
• import and calibration of raster maps to UTM coordinates or latitude/longitude
• raster map overlays with data grids
• new graphical data editing tools
• improved data and survey editing capabilities
• many new data imports as well as extended data and model export capabilities
• aeromagnetic compensation techniques
• magnetic base station corrections
• standard gravity data processing is now available in QCTool which is included with all Gravity licenses
• many new processing features are now in QCTool which is bundled with EMIGMA to provide all pre-processing to your interpretations

New visualization capabilities have been developed:

• a new tool for viewing data versus pseudo-depths
• a new tool for analyzing 1D inversions as geoelectric sections
• new tools for building 3D models in conjunction with data
• improved image exports in both raster and vector formats
• a new MULITIGRID tool
• coordinate system transformations - (e.g. local grid to a world grid and vice-versa)
• data stacking to allow data analyses for data repeats

In January, 2006, the new release offered further spreadsheet functionalities facilitating work within large data sets. You can now specify the font of the spreadsheet and easily perform various manipulations with data, such as Copy and Paste or adding different files to each other. The latter feature is especially useful when your data have been collected at different times and you want to put them all together. Also added are two new channels providing time and date information for each row of data.

Included in the Fall/2005 release are point by point IGRF calculations for magnetics using the latest coefficients. Now in QCTool you may perform your "diurnal" and IGRF and drift corrections. Extensions have also been made to the "Append and Merge files" functions.

In particular, we are offering our exceptional airborne TEM and FEM inversions at very competitive prices as well as 3D inversions of airborne magnetic and gravity data. Our specialty, however, is still in the inversion and modelling of ground TEM data. We also offer quality control services for your airborne and ground EM data. Please contact Sales if you are interested in discussing these services.

While our capabilities to calculate exception coefficients for the compensation were well accepted in EMIGMA, many users felt that the actual processing of the survey data was too awkward, slow and difficult to integrate back to other databasing software. Since, QCTool has proven to be exceptional in its ease of use, extent of its functionality and ease of migrating to other databasing software, we have added the survey data correction function to QCTool.

The calculation of the coefficients still lies in EMIGMA with its varied tools both for cleaning and visualizing but the coefficients are easily exported for use in QCTool. This also offers the benefit that the EMIGMA dongle need not be carried to the survey area as the coefficients can be calculated at your home office and sent via the internet to the field.

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