5.2.3. Inversion

Here, the code h3dtdinv.exe and the input file h3dtdinv.inp (see format) are used to invert dBz/dt data. TDEM data were created in the example “forward modeling”. Gaussian noise was added to the synthetic data. The noise had a standard deviation of 1e-14 T/s + 10% the absolute value of each datum. Files relevant to this part of the example are in the sub-folder inv. Before running this example, you may want to do the following:

• Download and open the zip folder containing the entire H3DTD example (if not done already)

• Learn how to run code from command line

• Learn the format of the input file

To invert the synthetic data, the input file below was used:

The inversion reached the target data misfit on 4th trade-off parameter. The final model may slightly overfit the data, therefore we show the recovered model for the 3rd trade-off parameter (left) and the true model (right) below. A cutoff of 0.025 S/m has been used for both models.