4.1.3. Inversion Program

The inversion is carried out using the h3dtdinv.exe executable program and an input file that MUST be name h3dtdinv.inp. To run the executable, open a command window and type the following:

../../_images/run_h3dtdinv.png

4.1.3.1. Units

  • Electric field data: Ex, Ey and Ez in units V/m

  • Magnetic field data: Hx, Hy and Hz in units A/m.

  • Magnetic field data: dBx/dt, dBy/dt and -dBz/dt in units T/s. The vertical component of dB/dt is represented using -dBz/dt due to a long-standing plotting convention

  • Conductivity model: S/m

  • Reference/starting conductivity model: S/m

  • Model/interface weights: unitless

Important

Any combination of data, electric and or magnetic field components, can be be inverted. A specified flag at the start of the observations file can be used to omit columns or individual datums.

4.1.3.2. Output Files

The program h3dtdinv.exe creates the following output files:

  • dpred_0.txt data predicted using the starting model or forward model

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

  • dpred_xx.txt data predicted using model ‘xx’

  • inv.con: final conductivity model

  • h3dtd.log: log file for the inversion

  • h3dtd.out: stores details regarding the inversion