Modeling deformation in Julia

Hi everyone, a general question here about Finite elements in Julia.

I am trying to do something rather “simple”. Imaging a large body (3D), fully constrained.
In side there is a fault/fracture/weak zone inside. There is some displacement along this plane, and the medium/body deforms. I want to model this with FEM, it is very usual in my field but I though maybe one of the FEM packages of Julia could handle this.

Something like this:

Any idea where to start?

Is there an actual fault, so that the left and right part of the domain slide alongside the fault?

Yes! There might also me asperity on the fault. Although the displacement along the fault would be very small compare to the dimensions of the domain.

In that case I regret but I have nothing: As far as I know no one has programmed that in Julia yet.

Now that I think about it, for my case the fault is so small compare the domain, that I know the nodes at each side of the fault will slide, but not the entire domain.
I found this package with two example that approach my setting:

I will have to toy with them. Thanks for the help