| Forward modelling response selection and units | Physical property input starting model | Predicted Response output |
| Gz (mGal) Free-air | absolute density (g/cm ) cgs | GX, GY, GZ |
| Gz (mGal) Complete Bouguer | relative density contrasts (g/cm3) cgs | GX, GY, GZ |
| FTG (Eo) | Density (g/cm3) cgs | GIJ*, Invariants, curvatures, strike angle |
| AGG (Eo) | Density (g/cm3) cgs | GIJ, Invariants, curvatures, strike angle |
| Gzz (Eo) | Density (g/cm3) cgs | GIJ*, Invariants, curvatures, strike angle |
| Magnetic (nT) | Conventional susceptibility (SI) | Bx, By, Bz, B projected |
| Normalized total magnetization * | Normalized total magnetization vector (SI) * | Bx, By, Bz, B projected |
| FDEM conductivity (ppm) | Conductivity (S/m) | ppm for specified frequencies (in-phase response) |
| ppm for specified frequencies (quadrature response) | ||
| IP and resistivity conductivity | Conductivity (S/m) | Current normalized voltage (V/A) |
| Volts for potential by default (unless specified as mV in the database) | ||
| Amps for current by default (unless specified as mA in the database) | ||
| IP and resistivity linear calculations of apparent chargeability | Since the calculation of apparent chargeability is linear and dimensionless, the starting model is also dimensionless. | The response is a dimensionless quantity that is calculated linearly from the starting model. |
| apparent chargeability, apparent metal factor (MF), and apparent percent frequency effect (PFE) | ||
| Dimensionless | ||
| IP and resistivity non-linear calculations of apparent peak chargeability | Dimensionless (V/V) | Dimensionless (V/V) |
| Vs/Vp (V/V) | ||
| Spectral IP complex conductivity | conductivity amplitude (S/m) | Complex conductivity amplitude (V) |
| conductivity phase (rad) | Complex conductivity phase (rad) | |
| Amplitude (V) | ||
| Phase (rad) | ||
| Spectral IP conductivity amplitude | Conductivity amplitude (S/m) | Complex conductivity amplitude (V) |
| Complex conductivity phase (rad) | ||
| Amplitude (V) | ||
| Phase (rad) | ||
| Spectral IP conductivity phase | Conductivity phase (rad) | Complex conductivity amplitude (V) |
| Complex conductivity phase (rad) | ||
| Amplitude (V) | ||
| Phase (rad) |
* GIJ denotes the 6 full tensor components
* Constructed from 3 orthogonal (Cartesian) components of magnetization. The total magnetization vector is a dimensionless quantity analogous to
susceptibility in SI.
It is defined as the magnetization M (A/m) divided by the inducing field strength H in (A/m). For only induced sources, this quantity is effectively
the conventional susceptibility
| Inverse response selection* and units | Physical Property | Predicted response output |
| Gz mGal (Complete Bouguer) | Density (g/cm3) cgs | Gz measured, Gz residual, background trend, error misfit, predicted response |
| FTG Eo | Density (g/cm3) cgs | 6 x GIJ measured, 6 x GIJ residual, 6 x background trend, 6 x error misfit, 6 x predicted response |
| AGG Eo | Density (g/cm3) cgs | ANE, BNE, AUV, BUV measured, 4x residual, 4x background trend, 4x error misfit, 4x predicted response |
| Gzz Eo | Density (g/cm3) cgs | Gzz measured, Gzz residual, background trend, error misfit, predicted response |
| Residual magnetic (intensity) - 'RMI' (nT) | Susceptibility (SI) | 'RMI' measured, RMI residual, background trend, error misfit, predicited response (projected and X,Y,Z componentns) |
| Residual magnetic (intensity) - 'RMI' (nT) | Total mangeization vector and components (SI, normalized) | 'RMI' measured, RMI residual, background trend, error misfit, predicited response (projected and X,Y,Z componentns) |
| FDEM Conductivity (ppm) | Conductivity (S/m) | Measured FDEM response for each frequency component (ppm), Assigned error to each measurement (ppm), predicted FDEM response for each frequency component (ppm) |
| IP and resistivity conductivity | Conductivity (S/m) | Current normalized voltage (V/A) |
| Volts for potential by default (unless specified as mV in the database) | ||
| Amps for current by default (unless specified as mA in the database) | ||
| IP and resistivity: linear calculations of chargeability | Since the calculation of apparent chargeability is linear and dimensionless, the inversion model is also dimensionless. | The response is a dimensionless quantity that is calculated linearly from the inversion result. |
| apparent chargeability, apparent metal factor (MF), and apparent percent frequency effect (PFE) | ||
| Dimensionless | ||
| IP and resistivity non-linear calculations of apparent peak chargeability | Dimensionless (V/V) | Dimensionless (V/V) |
| Vs/Vp (V/V) | ||
| Spectral IP complex conductivity | conductivity amplitude (S/m) | Complex conductivity amplitude (V) |
| conductivity phase (rad) | Complex conductivity phase (rad) | |
| Amplitude (V) | ||
| Phase (rad) | ||
| Spectral IP conductivity amplitude | Conductivity amplitude (S/m) | Complex conductivity amplitude (V) |
| Complex conductivity phase (rad) | ||
| Amplitude (V) | ||
| Phase (rad) | ||
| Spectral IP conductivity phase | Conductivity phase (rad) | Complex conductivity amplitude (V) |
| Complex conductivity phase (rad) | ||
| Amplitude (V) | ||
| Phase (rad) |
* we model the geophysical property variation rather than the absolute value of the property. Hence you cannot invert Free-air gravity directly without prior modelling
of the terrain correction. Total field magnetic input may be problematic over large regions, due to the Earth’s field variation.