Fractal

The Fractal tool creates terrains based on fractal patterns. It can be applied to an existing image and it can be applied gradually.

To use the fractal tool:

Click the Elevation tab.
Left-click on the triangle icon next to the Fractal effect:
Select a fractal type from the menu that comes up:
Click on the Fractal effect button to apply the effect 100% or drag right slowly to apply the effect in increments.
If you don't like the effect, Undo the change or click the Fractal effect button again to see a new variation.