The simple (and maybe not visually impressive) way would be to have 2 heightfields with the features of the separate plates, animate their positions, and then use a Painted Shader mask along the collision area to mask a Power Fractal, with the Displacement Amplitude of the Power Fractal also animated, increasing dramatically at the moment of impact. There are some variations on that which would work, perhaps better, but that's the basic idea. I'm sure there are better overall methods.
- Oshyan