[barbariangrunge]

I think we sort of have the tech to use geological energy, but I imagine the hardest part is not having your equipment destroyed all the time by quakes? You'd probably want to put your collectors deep underground where there's more activity

[sandworm101]

At a theoretical level, it could be done with ropes. You don't need to wait for earthquakes. Setup two anchors on either side of a fault. String ropes between them. As the two plates slowly more, the stretching ropes can be tied to generators. Totally theoretical but, no new physics is required to extract energy from two slowly moving things.