shifting vs volcanic

shifting

noun
  • The phenomenon by which two or more constituents appearing on the same side of their common head exchange positions to obtain non-canonical order. 

  • A shift or change; a shifting movement. 

volcanic

noun
  • A volcanic rock. 

adj
  • Of or pertaining to a volcano or volcanoes 

  • Produced by a volcano, or, more generally, by igneous agencies 

  • Changed or affected by the heat of a volcano. 

  • Reminiscent of a volcano; explosive, violent, full of suppressed anger, energy etc. 

How often have the words shifting and volcanic occurred in a corpus of books? (source: Google Ngram Viewer )