In piano music there's the technique called blind octaves where you create a rumbling melody over three octaves by playing the melody itself with the thumbs of your left and right hands alternatively, each octaved with the fourth or fifth fingers. I am looking for the word to describe the equivalent, but with whole chords. That can either stay with the same chord throughout the passage: Or it can form a quasi-melody: Sometimes one hand plays octaves and the other chords: Finally, Alkan's Concerto for Solo Piano does this for two and a half minutes! In this video, from 23:50 to 26:20. This analysis calls it "alternate hands" or "alternate chords", but purely descriptively.
What is the general term for this technique, if there is one?