I never worked with geological data, so I was happy to explore this new field. I received the data from the Hessian Agency for Nature Conservation, Environment and Geology and I used it as a way to learn about geology and test the voxel layers in the ArcGIS Maps SDK for JavaScript.
The dataset which originally came in a netcdf format has 2 variables: lithology and permeability. 3D is the best way to visualize this, the change in lithology along the fault line immediately becomes apparent. The cool thing about voxel layers is that you can slice and section them in any direction, so you can see the data from any angle. For permeability, you can also create isosurfaces which show the areas of the same permeability value. This is a great way to visualize the data and see how it changes in 3D.
Play with the model yourself on https://labs.esri.com/geology-darmstadt/.