JOINTEM is geophysical modelling and interpretation software for:
a) geoelectrical dc soundings, a.k.a. vertical electric soundings (VES),
b) time-domain electromagnetic (TEM) soundings (single and central loop),
c) audiomagnetotelluric (AMT) soundings based on plane wave impedance, and
d) frequency-domain VLF-R measurements (single frequency).
The computation is based on one-dimensional (1-D) horizontally layered earth model. The model parameters are the electrical resistivity and thickness (or depth to the top) of the layers. Cole-Cole model parameters (chargeability, frequency factor, and time constant) can be used in TEM method to account for (induced) polarization and dispersion effects and the chargeability can be utilized in DC soundings. Optimization based on linearized inversion method with adaptive damping is used to minimize the difference between measured field data and synthetic data computed for the model. Both individual and joint inversion of DC, TEM, and AMT data is possible. VLF-R data measured at single frequency can be used as additional constraint.