DC and EM Joint Inversion

Hello, I would like to perform 2D plus 3D DC and EM forward modelling and joint inversion. After going through the SimPEG documentation and manuals, I couldn’t figure out the relevant modules and packages use to solve this problem. Kindly assist with the necessary explanations on how to go about it. Thank you so much.

Hi GeoPaul,

To perform joint inversion of several geophysical surveys that depend on a single physical property, you can use the Combo Objective function feature, which allows you to add any misfit terms together.

For example, if you have created a data misfit for DC (let call it dmis_dc) and a data misfit for EM (dmis_em), you can create a new data misfit that encompass both by writing:

dmis = 0.5 * dmis_em + 0.5 * dmis_dc (the 0.5 are just here to show that you can weight each one)

To create data misfit, it is the same as in the examples in the documentation.

Disclaimer: joint inversion is still an active area of research. As such, we are not providing (yet) tools that ensure that both surveys are fit at the same time, nor guidelines on how to weight each survey compared to each other; you will likely have to try several weighting strategies.