Gravity Structural Inversion

The Gravity Structural Inversion function modifies the elevation of the selected layer in order to minimize the gravity misfit. Inversion updates the calculated response and error to reflect the structural changes.

Perform a Gravity Structural Inversion

On the Calculate menu, select Gravity Structural Inversion. The Gravity Structural Inversion dialog appears.
This dialog can also be accessed by right-clicking the model layer in the Layers menu and selecting Gravity Structural Inversion.
From the dropdown list, select the Inversion Surface. This layer will be altered.
Enter a Maximum Number of Inversion Iterations. Inversion process will stop after this many iterations, even if the convergence target has not been reached.
Enter the Convergence Limit. Inversion will stop when either the mean error or the standard deviation of the error is less than this limit. Note that under certain conditions, the calculations may not converge at all. The algorithm attempts to detect this and terminate accordingly.
Enter the Lower High-Cut Limit. A cosine roll-off high-cut filter is applied to the error before inverting. This is the beginning of the cosine taper. The default value is equivalent to 0.5 times the Nyquist.
Enter the Upper High-Cut Limit (the short-wavelength end of the taper. The default is the wavelength equivalent to 0.7 times the Nyquist. If you enter numbers that are <= 1.0, they are interpreted as fractions of Nyquist. If you enter numbers that are > 1.0, they will be interpreted as wavelengths (distances) in ground units.
Enter the Regional Offset. This constant will be subtracted from the observed gravity before inverting.
Browse to the Constraints Grid. This controls where the inversion surface may change. Values of 0 indicate no change; 1 indicates maximum change.
Optionally, you may click Limits to activate a dialog that limits the amount of change possible during inversion.
Click Yes to continue.
If prompted, click Yes to recalculate. The calculation is processed.