4.1.6. IP Inversion

The program ipinv3d_55.exe performs the 3D inversion of IP data on tensor meshes.

4.1.6.1. Running the Program

To run the executable, open a command window and type the following:

../../_images/run_ipinv.png

Essentially you are calling the path to the executable followed by the path to the input file .

4.1.6.2. Units

  • IP data: Depends on the IP data type set in the observations file, the data are either secondary voltage or apparent chargeability

  • Background conductivity model: S/m

  • Chargeability model: chargeability in whatever units you had as apparent chargeability data.

Note

IP data are inverted using a linearized formulation. If the data are apparent chargeabilities, the recovered chargeability model will be in the same units as the data. That is, you could invert apparent chargeability data that have units V/V, mV/V or ms and the recovered chargeability model would have units V/V, mV/V and ms, respectively.

4.1.6.3. Output Files

The program ipinv3d_55.exe creates the following output files:

  • ipinv3d_xx.con: recovered model at iteration ‘xx’

  • ipinv3d_xx.pre data predicted using model ‘xx’

  • ipinv3d.log: log file for the inversion

  • ipinv3d.out: stores details regarding the convergence of the inversion

  • sensitivity.txt: the average sensitivities of the cells for the latest recovered model.

  • obs.loc: if the survey file used surface format, the code will output a general locations file that contains the elevations of the electrodes projected to the discrete topography.